Introduction to Teradata SQL

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Introduction to Teradata SQL (Module 1)

Objectives
After completing this module, you should be able to:

Describe the structure of a Relational Database Management System (RDBMS).
Explain the role of Structured Query Language (SQL) in accessing a Relational Database.
List the three categories of SQL statements and describe their function.

What is an RDBMS?

Data is organized into tables in a relational database management system (RDBMS). Rows in the
table represent instances of an entity, in this case an employee or a department. Columns
represent the data fields which comprise the rows. Relations between tables occur when a
column in one table also appears as a column in another.

Here is an example of two related tables:

Can you answer the following questions using the tables above?

Question 1: What is the department name for employee 1004?

Question 2: Who is the manager of employee 1004?

What is SQL?

Structured Query Language (SQL) is the industry standard language for communicating with
Relational Database Management Systems. SQL is used to look up data in relational tables,
create tables, insert data into tables, grant permissions and many other things.

Structured Query Language is used to define the answer set that is returned from the Teradata
Database.

SQL is a non-procedural language, meaning it contains no procedural-type statements such as
those listed here:

GO TO
PERFORM
DO LOOP
OPEN FILE

CLOSE FILE
END OF FILE

SQL Commands

SQL statements commonly are divided into three categories:

1. Data Definition Language (DDL) - Used to define and create database objects such as
tables, views, macros, databases, and users.
2. Data Manipulation Language (DML) - Used to work with the data, including such tasks
as inserting data rows into a table, updating an existing row, or performing queries on the
data. The focal point of this course will be on SQL statements in this category.
3. Data Control Language (DCL) - Used for administrative tasks such as granting and
revoking privileges to database objects or controlling ownership of those objects. DCL
statements will not be covered in detail in this course. For complete Data Control
Language coverage, please see the NCR Customer Education "Teradata Database
Administration" course.

Data Definition Language (DDL) Examples

SQL statement Function
CREATE Define a table, view, macro, index, trigger or stored procedure.
DROP Remove a table, view, macro, index, trigger or stored procedure.
ALTER Change table structure or protection definition.

Data Manipulation Language (DML)

SELECT Select data from one or more tables.
INSERT Place a new row into a table.
UPDATE Change data values in one or more existing rows.
DELETE Remove one or more rows from a table.

Data Control Language (DCL)

GRANT Give user privileges.
REVOKE Remove user privileges.
GIVE Transfer database ownership.

Relational Concepts

The figure below illustrates six rows of a much larger table.

Some interesting things to note about this table:

The intersection of a row and a column is a data value. Data values come from a
particular domain. Domains represent the pool of legal values for a column. For example,
the data values in the EMPLOYEE NUMBER and MANAGER EMPLOYEE NUMBER come from the
same domain because both columns come from the pool of employee numbers. The
domain of employee numbers might be defined as the pool of integers greater than zero.
The EMPLOYEE NUMBER column is marked PK, which indicates that this column holds the
Primary Key. The next 3 columns are marked FK, which stands for Foreign Key.
The purpose of the Primary Key is to uniquely identify each record. No two values in a
primary key column can be identical.
A Foreign Key represents the Primary Key of another table. Relationships between tables
are formed through the use of Foreign Keys.

Teradata SQL (Module 2)

Objectives


Describe the uses of the Teradata SQL SELECT statement.
Retrieve data from a relational table using the SELECT statement.
Use the SQL ORDER BY and DISTINCT options.
Set a default database using the DATABASE command.
Write SQL statements using recommended coding conventions.
Name database objects according to Teradata SQL rules.

SELECT

Structured Query Language (SQL) consists of three types of statements, previously defined
as:

Data Definition Language (DDL)

- Used to create, drop and modify objects
Data Manipulation Language(DML)

- Used to add, delete, update and read data rows in a table
Data Control Language(DCL)
- Used to implement security and control on database objects.

Our focus in this course will be mostly on the DML portion of the language. We will first look at the
SELECT statement.

The SELECT statement allows you to retrieve data from one or more tables. In its most common form,
you specify certain rows to be returned as shown.

SELECT *
FROM employee
WHERE department_number = 401;

The asterisk, "*", indicates that we wish to see all of the columns in the table. The FROM clause
specifies from which table in our database to retrieve the rows. The WHERE clause acts as a filter
which returns only rows that meet the specified condition, in this case, records of employees in
department 401.

Note: SQL does not require a trailing semicolon to end a statement but the Basic Teradata Query
(BTEQ) utility that we use to enter SQL commands does require it. All examples in this course will
include the semicolon.

What if we had not specified a WHERE clause.

SELECT * FROM employee;

This query would return all columns and all rows from the employee table.

Instead of using the asterisk symbol to specify all columns, we could name specific columns
separated by commas:

SELECT employee_number
,hire_date
,last_name
,first_name
FROM employee
employee_number hire_date last_name first_name
-------------------- ---------- ----------- -----------
1004 76/10/15 Johnson Darlene
1003 76/07/31 Trader James
1013 77/04/01 Phillips Charles
1010 77/03/01 Rogers Frank
1022 79/03/01 Machado Albert
1001 76/06/18 Hoover William
1002 76/07/31 Brown Alan

Unsorted Results

Results come back unsorted unless you specify that you want them sorted in a certain way. How
to retrieve ordered results is covered in the next section.

ORDER BY Clause

Use the ORDER BY clause to have your results displayed in a sorted order. Without the ORDER
BY clause, resulting output rows are displayed in a random sequence.

,last_name
,first_name
,hire_date
FROM employee
WHERE department_number = 401
ORDER BY hire_date;

Sort Direction

In the example above, results will be returned in ascending order by hire date. Ascending order
is the default sort sequence for an ORDER BY clause. To explicitly specify ascending or

descending order, add ASC or DESC, to the end of the ORDER BY clause. The following is an
example of a sort using descending sequence.

ORDER BY hire_date DESC;

Naming the Sort Column

You may indicate the sort column by naming it directly (e.g., hire_date) or by specifying its
position within the SELECT statement. Since hire_date is the fourth column in the SELECT
statement, the following ORDER BY clause is equivalent to saying ORDER BY hire_date.

ORDER BY 4;

Multiple ORDER BY Columns

An ORDER BY clause may specify multiple columns. No single column in an ORDER BY clause
should exceed a length of 4096 bytes, otherwise it will be truncated for sorting purposes.

The order in which columns are listed in the ORDER BY clause is significant. The column named
first is the major sort column. The second and subsequent are minor sort columns. In the
following example, results are sorted by department number in ascending order. Where
multiple records share the same department number, those rows are sorted by job_code in
ascending order. The following are examples:

,department_number
,job_code
FROM employee
WHERE department_number < 302
ORDER BY department_number
,job_code;
employee_number department_number job_code
-------------------- ---------------------- ----------
801 100 111100
1025 201 211100
1021 201 222101
1019 301 311100
1006 301 312101
1008 301 312102

Note: Each column specified in the ORDER BY clause can have its own sort order, either
ascending or descending.

,department_number
,job_code
FROM employee
WHERE department_number < 302
ORDER BY department_number ASC
,job_code DESC;

employee_number department_number job_code
-------------------- ---------------------- ----------
801 100 111100
1021 201 222101
1025 201 211100
1008 301 312102
1006 301 312101
1019 301 311100

DISTINCT

The DISTINCT operator will consolidate duplicate output rows to a single occurrence.

Example Without DISTINCT

SELECT department_number
,job_code
FROM employee
department_number job_code
---------------------- ----------
501 512101
501 512101
501 511100

Note: Two people in department 501 have the same job code (512101). If our purpose is
simply to find out which job codes exist in department 501, we could use DISTINCT to avoid
seeing duplicate rows.

Example With DISTINCT

SELECT DISTINCT department_number
,job_code
FROM employee
department_number job_code
---------------------- ----------
501 511100
501 512101

Note: DISTINCT appears directly after SELECT, and before the first named column. It may
appear to apply only to the first column, but in fact, DISTINCT applies to all columns named in
the query. Two rows in our result example set both have department_number 501. The
combination of department_number and job_code are distinct since the job codes differ.

Naming Database Objects

All Teradata objects, such as tables, must be assigned a name by the user when they are

created.

These rules for naming objects are summarized as follows:

Names are composed of: a-z
A-Z
0-9
_ (underscore)
$
#

Names are limited to 30 characters.
Names cannot begin with a number.

Teradata names are not case-sensitive.

Examples of valid names:

Accounts
Accounts_2005
accounts_over_$2000
Account#

Equivalence

Accounts and accounts represent the same table. Case is not considered.

Naming Rules

Naming Syntax

Database names and User names must be unique within the Teradata Database.
Table, view, macro, trigger, index and stored procedure names must be unique within
a Database or User.
Column names must be unique within a Table.

The syntax for fully qualifying a column name is:

Databasename.Tablename.Columnname
Example
NAME (unqualified)

EMPLOYEE.NAME (partially qualified)

PAYROLL.EMPLOYEE.NAME (fully qualified)

Note: The amount of qualification necessary is a function of your default database setting.

Coding Conventions

SQL is considered a 'free form' language, that is, it can cover multiple lines of code and there
is no restriction on how much 'white space' (i.e., blanks, tabs, carriage returns) may be
embedded in the query. Having said that, SQL is syntactically a very precise language.
Misplaced commas, periods and parenthesis will always generate a syntax error.

The following coding conventions are recommended because they make it easier to read,
create, and change SQL statements.

Recommended Practice

SELECT last_name
,first_name
,hire_date
,salary_amount
FROM employee
ORDER BY last_name;

Not Recommended Practice

select last_name, first_name, hire_date, salary_amount
from employee where department_number = 401 order by last_name;

The first example is easy to read and troubleshoot (if necessary). The second example
appears to be a jumble of words. Both, however, are valid SQL statements.

Default Database

Setting the Default Database

As a valid user, you will normally have access rights to your own user database and the
objects it contains. You may also have permission to access objects in other databases.

The user name you logon with is usually your default database. (This depends on how you
were created as a user.)

For example, if you log on as:

.logon rayc;

password: xyz

then "rayc" is normally your default database.

Note the dot (.) before "logon". Commands that begin with a dot are BTEQ commands, not
SQL commands. The BTEQ command processor will read this command; the SQL processor
will not see it.

Queries you make that do not specify the database name will be made against your default
database.

Changing the Default Database

The DATABASE command is used to change your default database.

For example:

DATABASE payroll;
sets your default database to payroll. Subsequent queries (assuming the proper privileges are
held) are made against the payroll database.

Lab

For this set of lab questions you will need information from the Database Info document.

These exercises are to be done as a pencil-and-paper workshop. Write SQL statements as
you would enter them on-line. Click on the buttons to the left to see the answers.

Question 3:

A. Select all columns for all departments from the department table.
B. Using the employee table, generate a report of employee last and first names and
salary for all of manager 1019's employees. Order the report in last name ascending
sequence.
C. Modify the previous request to show department number instead of first name. Make
it for manager 801's employees instead of manager 1019's.
D. Prepare a report of the department numbers and the manager's employee numbers
for everyone in the employee table. Now add the DISTINCT option to the same report.

Note: Save your answers for this Lab, as you actually enter and run these exercises using
BTEQ scripts for the Labs in Module 3.

Simple BTEQ (Module 3)

Objectives


Use BTEQ to submit SQL to the Teradata database.
Set session parameters to enable
 Teradata transaction semantics.
 The SQL Flagger.

What is BTEQ?

BTEQ is a front end tool for submitting SQL queries. 'BTEQ' stands for Basic Teradata Query
program.

BTEQ is client software that resides on your network or channel-attached host. After starting
BTEQ, you will log on to Teradata using a TDP-id (Teradata Director Program id), your user
id and password. The TDP-id identifies the instance of Teradata you are going to access.

TDP's come in two varieties - the standard TDP for channel-attached clients, and the Micro-
TDP (or MTDP) for network-attached clients.

They are involved in getting your SQL requests routed to a Parsing Engine (PE) which
validates your request and passes it to the Access Module Processors (AMPs). AMPs retrieve
the answer sets from the disks and send the response set back to the PE which in turn
forwards it to the TDP and ultimately back to you at your session.

Where is BTEQ Located?

BTEQ is Teradata client software which is installed on mainframe hosts or network attached
clients. It operates under all host systems and local area networks (LANs).

BTEQ Commands

Facts about BTEQ commands:

Must be preceded by a period (.) or terminated by a semi-colon or both.
Provide an output listing (an audit trail) of what occurred.
Additional commands for report formatting are available.
Are not case-sensitive.

Invoking BTEQ varies somewhat depending on the platform. In the UNIX enviroment, simply
typing in the command 'bteq' is required.

For purposes of this course, instructions for starting a lab session are contained on each lab
page.

Using BTEQ Interactively

Submitting SQL Statements with BTEQ

There are two ways to submit SQL statements to BTEQ in interactive mode:

Type in SQL statements directly to the BTEQ prompt.
Open another window with a text editor. Compose SQL statements using the text
editor, then cut and paste the SQL to the BTEQ prompt.

When users log on to BTEQ, they are by default assigned a single session.

Session Parameters

Session parameters include transaction semantics and the SQL Flagger.

Transaction semantics, allows you to set your session in either ANSI or Teradata (BTET)
mode. All features of Teradata SQL will work in either mode, but each mode activates
different case-sensitivity and data conversion defaults, and so the same query might return
different results in each mode.

For purposes of this course, Teradata-mode sessions will be assumed unless otherwise
specified. More on these session parameters is covered in the Teradata SQL Advanced WBT.

Example

.SET SESSION TRANSACTION ANSI; /* Sets ANSI mode*/

.SET SESSION TRANSACTION BTET; /* Sets Teradata mode*/

Note: All text between /* and */ are treated as comments by BTEQ.

You may also activate the ANSI Flagger, which automatically flags non-ANSI compliant
syntax with a warning but still returns the expected answer set.

Example

.SET SESSION SQLFLAG ENTRY; /* Causes non-Entry level ANSI syntax to be
flagged */

SELECT DATE; /* Causes a warning because keyword DATE is not ANSI
standard*/

*** SQL Warning 5821 Built-in values DATE and TIME are not ANSI.
*** Query completed. One row found. One column returned.
*** Total elapsed time was 1 seconds.

Date
--------
05/01/12

Example

.SET SESSION SQLFLAG NONE /* Disables ANSI Flagger*/

SELECT DATE; /* DATE keyword is not flagged */

*** Query completed. One row found. One column returned.
*** Total elapsed time was 1 second.

Date
--------
05/01/12

Note: In both cases, the date was returned.

You need to establish your session parameters prior to logging on. Teradata extensions
cannot be disabled, but they can be flagged using the ANSI flagger.

The SHOW CONTROL Command

The BTEQ .SHOW CONTROL command displays BTEQ settings. The following output shows
the result of this command.

.SHOW CONTROL

Default Maximum Byte Count = 4096
Default Multiple Maximum Byte Count = 2048
Current Response Byte Count = 4096
Maximum number of sessions = 20
Maximum number of the request size = 32000

EXPORT RESET
IMPORT FIELD
LOGON L7544/tdxxx
RUN
[SET] ECHOREQ = ON
[SET] ERRORLEVEL = ON
[SET] FOLDLINE = OFF ALL
[SET] FOOTING = NULL
[SET] FORMAT = OFF
[SET] FORMCHAR = OFF
[SET] FULLYEAR = OFF
[SET] HEADING = NULL
[SET] INDICDATA = OFF
[SET] NOTIFY = OFF
[SET] NULL = ?
[SET] OMIT = OFF ALL
[SET] PAGEBREAK = OFF ALL
[SET] PAGELENGTH = 55
[SET] QUIET = OFF
[SET] RECORDMODE = OFF
[SET] REPEATSTOP = OFF

[SET] RETCANCEL = OFF
[SET] RETLIMIT = No Limit
[SET] REPEATSTOP = OFF
[SET] RETCANCEL = OFF
[SET] RETLIMIT = No Limit
[SET] RETRY = ON
[SET] RTITLE = NULL
[SET] SECURITY = NONE
[SET] SEPARATOR = two blanks
[SET] SESSION CHARSET = ASCII
[SET] SESSION SQLFLAG = NONE
[SET] SESSION TRANSACTION = BTET
[SET] SESSIONS = 1
[SET] SIDETITLES = OFF for the normal report.
[SET] SKIPDOUBLE = OFF ALL
[SET] SKIPLINE = OFF ALL
[SET] SUPPRESS = OFF ALL
[SET] TDP = L7544
[SET] TIMEMSG = DEFAULT
[SET] TITLEDASHES = ON for the normal report.
[SET] UNDERLINE = OFF ALL
[SET] WIDTH = 75

BTEQ Scripts

A BTEQ script is a file that contains BTEQ commands and SQL statements. A script is built
for sequences of commands that are to be executed on more than one occasion, i.e.
monthly, weekly, daily.

How to create a BTEQ Script

To create and edit a BTEQ script, use an editor on your client workstation. For example, on
a UNIX workstation, use either the vi or text editor.

How to Submit a BTEQ Script

Start BTEQ, then enter the following BTEQ command to submit a BTEQ script:

.run file = <scriptname>

BTEQ Comments -- Teradata Extensions

The Teradata RDBMS supports comments that span multiple lines by using the "/*" and
"*/" as delimiters.

Example of a BTEQ comment:

/* You can include comments in a BTEQ
script by enclosing the comment text between “/*” and “*/”
and the comment may span multiple lines */

Script Example

Let's look at an example of a BTEQ script using ANSI standard comments. The ANSI
comment delimiter is the double dash, --.

(This script is named mod2exer.scr )

.SET SESSION TRANSACTION ANSI
.LOGON L7544/tdxxx,;

-- Obtain a list of the department numbers and names
-- from the department table.

,department_name
FROM department;

.QUIT

Note: Both Teradata style (/* */) and ANSI style (--) comments may be included in any
SQL command script.

To Execute The Script:

.run file=mod2exer.scr

(The following is the output generated by the above command.)

Script started on Sat Feb 15 10:48:19 1997
$ bteq

Teradata BTEQ 04.00.01.00 for UNIX5. Enter your logon or BTEQ command:

.run file=mod2exer.scr (this is the only user input; the rest of the commands came from
file mod2exer.scr)

.run file=mod2exer.scr

.LOGON L7544/tdxxx,

*** Logon successfully completed.
*** Transaction Semantics are ANSI.
*** Character Set Name is 'ASCII'.

BTEQ -- Enter your DBC/SQL request or BTEQ command:
-- Obtain a list of the department numbers and names

-- from the department table.

,department_name
FROM department;

*** Query completed. 9 rows found. 2 columns returned.

department_number department_name
------------------ -----------------
401 customer support

<rest of result rows are not shown in this screen capture>


.QUIT
*** You are now logged off from the DBC.
*** Exiting BTEQ...
*** RC (return code) = 0
# exit

Using BTEQ in BATCH Mode

If you prefer to write all SQL statements in a single script file, there are two ways you
may execute the script:

Start BTEQ in interactive mode. Use the following BTEQ command to execute the
script:

.run file = mod2exer.scr

Start BTEQ and redirect standard input to use the script file.

$bteq < mod2exer.scr

(Note: The dollar sign ‗$‘ corresponds to the UNIX prompt.)

How to Capture BTEQ Session Output

From a UNIX workstation, use the script <filename> command to capture the output of
your session :

$script <filename> Logs all input and output to <filename>.
$bteq Starts BTEQ in interactive mode.
.run file = <scriptname> Submits pre-written script which contains BTEQ

commands and SQL statements.

The contents of <scriptname> and responses from the Teradata database will be output
to both the screen and the designated <filename> if one has been designated.

How to Stop Capturing BTEQ Session Output

From a UNIX workstation, issue the following UNIX command to stop the script
command:

$exit
This closes the logging file but does not terminate the UNIX session.

Identifying Syntax Errors

BTEQ output results will display a "$" to indicate the location where the error was
detected in either the script or request. The following is an example of captured output
showing a syntax error:

Script started on Thu Oct 24 16:21:21 1996
# bteq
…


.logon L7544/tdxxx,

*** Logon successfully completed.
*** Transaction Semantics are ANSI.
*** Character Set Name is 'ASCII'.


,DISTINCT department_name
FROM department;
,DISTINCT department_name
$
*** Failure 3708 Syntax error, 'DISTINCT' that follows the ',' should be
deleted.

Statement# 1, Info =36
*** Total elapsed time was 1 second

.BTEQ -- Enter your DBC/SQL request or BTEQ command:

.quit
*** You are now logged off from the DBC.
*** Exiting BTEQ...
*** RC (return code) = 8
# exit

script done on Thu Oct 24 16:21:39 1996

The dollar sign points to the command DISTINCT. The error text tells us that DISTINCT
should be deleted. The DISTINCT command must directly follow the SELECT command in
your request.

Lab

To start the online labs, click on the Telnet button in the lower left hand screen of the
course. Two windows will pop-up: a BTEQ Instruction Screen and your Telnet Window.
Sometimes the BTEQ Instructions get hidden behind the Telnet Window.
You will need these instructions to log on to Teradata.

Be sure to change your default database to the Customer_Service database in
order to run these labs.

Question 4:

A. See Labs A, B, and C from Module 2 that you did on paper. You can use NotePad or
another text editor to create your SQL requests again, and then simply copy and
paste them into the Telnet window after you've logged on with BTEQ.
B. Use BTEQ to submit your two reports from Lab D in Module 2. Observe the number
of rows returned in your output. Which rows were eliminated due to the DISTINCT
option?

Click on the Lab B button to see the answer for this Lab.

C. Set the ANSI Flagger ON and observe the differences it produces.

Do this by:

Logging off of Teradata (.logoff).
Setting the flagger on (.SET SESSION SQLFLAG ENTRY).
Relogging on to Teradata

Resubmit your query from Lab A.1.
What differences do you observe?
Why?

(Note: the ANSI Flagger is covered in more detail in SQL Level 3.)

Click on the Lab C button to see the answer for this Lab.

D. 1) Determine the default system session transaction mode. What command did
you use?

2) Set the session transaction mode to the opposite setting (e.g., set it to ANSI if
the system default is BTET) then verify the new setting.

Click on the Lab D button to see the answer for this Lab.

Lab Answer A.A
DATABASE Customer_Service;
SELECT * FROM department ORDER BY 1;

*** Query completed. 9 rows found. 4 columns returned. *** Total elapsed time was 1 second.

department_number department_name budget_amount manager_employee_number
----------------------- --------------------- ------------------ ---------------------------------
100 president 400000.00 801
401 customer support 982300.00 1003
403 education 932000.00 1005
402 software support 308000.00 1011
302 product planning 226000.00 1016
501 marketing sales 308000.00 1017
301 research and development 465600.00 1019
201 technical operations 293800.00 1025
600 None ? 1099

Note: Order is random. And user input is highlighted in red

Lab Answer A.B

SELECT last_name
,first_name
,salary_amount
FROM employee
WHERE manager_employee_number = 1019
ORDER BY last_name
;

last-name first-name salary-amount
Kanieski Carol 29250.00
Stein John 29450.00

Lab Answer A.C

SELECT last_name
,department_number
,salary_amount
FROM employee
WHERE manager_employee_number = 801
ORDER BY last_name
;

last_name department_number salary_amount
Daly 402 52500.00
Kubic 301 57700.00
Rogers 302 56500.00
Runyon 501 66000.00
Ryan 403 31200.00
Short 201 34700.00
Trader 401 37850.00
Trainer 100 100000.00

Lab Answer B

,manager_employee_number
FROM employee
;

department_number manager_employee_number

301 1019
501 801
100 801
401 801
402 1011
301 801
301 1019
402 801
401 1003
403 1005
401 1003
403 1005
403 801
201 801
201 1025
501 1017
403 1005
501 1017
401 1003
401 1003
401 1003
403 1005
403 1005
401 1003
501 1017
302 801

SELECT DISTINCT
department_number
FROM employee
;

department_number manager_employee_number

100 801
201 801
201 1025
301 801
301 1019
302 801
401 801
401 1003

402 801
402 1011
403 801
403 1005
501 801
501 1017

Lab Answer C

Note: Actual warning messages generated will vary depending on how you have
written your queries. Remember that ANSI does not support any lower case syntax.

.SET SESSION SQLFLAG ENTRY

.LOGON RPC1042/tdxxx;

SELECT *
FROM department
;


FROM department
$
*** SQL Warning 5836 Token is not an entry level ANSI Identifier or
Keyword.

department_number department_name budget_amount
manager_employ
----------------- ----------------------- ------------- --------
------
100 president 400000.00
801
401 customer support 982300.00
1003
403 education 932000.00
1005
402 software support 308000.00
1011
302 product planning 226000.00
1016
501 marketing sales 308000.00
1017
301 research and development 465600.00
1019
201 technical operations 293800.00
1025
600 None ?
1099
The warning message is generated because the ANSI flagger is enabled
and is reporting that ANSI mode does not support lowercase syntax.

Lab Answer D

.SHOW CONTROL
.
.
.
[SET] SESSION SQLFLAG = ENTRY
[SET] SESSION TRANSACTION = BTET
.
.
.
.LOGOFF .SET SESSION TRANSACTION ANSI
.SHOW CONTROL
.
.
.
[SET] SESSION SQLFLAG = ENTRY
[SET] SESSION TRANSACTION = ANSI
.
.
.

HELP Functions Module 4

Objectives

After completing of this module, you should be able to:

Obtain the definition of an existing Database, Table, View, or Macro using the
HELP and SHOW statements.
Determine how the Teradata RDBMS will process a SQL request using the
EXPLAIN statement.

Teradata SQL Extensions

Several commands in our software are Teradata-specific. Here is a list of Teradata
extensions covered within this course.

ADD_MONTHS BEGIN/ END TRANSACTION
COLLECT/ DROP COMMENT ON
STATISTICS
CONCATENATION EXPLAIN
FALLBACK FORMAT

HELP INDEX
LOCKING MACRO Facility

• CREATE
• REPLACE
• DROP
• EXECUTE
NAMED NULLIFZERO/ZEROIFNULL
SHOW SUBSTR
TITLE TRIM
WITH WITH . . . BY

In this module, we focus on the following functions:

EXPLAIN
HELP
SHOW

HELP Commands: Database objects

The HELP Command is used to display information about database objects such as (but
not limited to):

Databases and Users
Tables
Views
Macros

HELP retrieves information about these objects from the Data Dictionary. Below are the
syntactical options for various forms of the HELP command:

HELP Command

HELP DATABASE databasename;
HELP USER username;
HELP TABLE tablename;
HELP VIEW viewname;
HELP MACRO macroname;
HELP COLUMN table or viewname.*; (all columns)
HELP COLUMN table or viewname.colname . . ., colname;

Some of the other HELP commands which will be seen later in this course include:

HELP INDEX tablename;
HELP STATISTICS tablename;
HELP CONSTRAINT constraintname;
HELP JOIN INDEX join_indexname;
HELP TRIGGER triggername;

The HELP DATABASE Command

The HELP DATABASE command in the following example shows all objects in the
Customer_Service database. Objects may be recognized by their 'Kind' designation as
follows:

Table =T
View =V
Macro =M
Trigger =G
Join Index =J
Stored Procedure =P

HELP DATABASE Customer_Service;

Results will be displayed as follows:

Table/View/Macro Kind Comment
Name
contact T ?
customer T ?
department T ?
employee T ?
employee_phone T ?
job T ?
location T ?
location_employee T ?
location_phone T ?

All objects in this database are tables. The '?' is how BTEQ displays a null, indicating that
no user comments have been entered.

Note: To return HELP information on an object, a user must either own the object or
have at least one privilege on it.

The HELP TABLE Command

The HELP TABLE command shows the name, data type, and comment (if applicable), of
all columns in the specified table:

HELP TABLE Customer_Service.employee
ColumnName Type Comment
employee_number I System assigned identification
manager_employee_number I ?
department_number I Department employee works
in
job_code I Job classification designation
last_name CF Employee surname
first_name CV Employee given name
hire_date DA Date employee was hired
birthdate DA ?
salary_amount D Annual compensation amount

Data types are as follows:

Type Description Type Description
CF CHARACTER FIXED F FLOAT
CV CHARACTER VARIABLE BF BYTE
D DECIMAL BV VARBYTE
DA DATE AT TIME
I INTEGER TS TIMESTAMP
I1 BYTEINT
I2 SMALLINT

HELP Commands: Session Characteristics

Use the HELP SESSION; command to see specific information about your SQL session.
The following displays the user name with which you logged in log-on date and time,
your default database, and other information related to your current session:

User Name DBC
Account Name DBC
Log on Date 05/02/18
Log on Time 11:54:46
Current DataBase DBC

Collation ASCII
Character Set ASCII
Transaction Semantics Teradata
Current DateForm IntegerDate
Session Time Zone 00:00
Default Character Type LATIN
Export Latin 1
Export Unicode 1
Export Unicode Adjust 0
Export KanjiSJIS 1
Export Graphic 0
Default Date Format None

To produce the formatting shown above use:

.SET FOLDLINE ON

.SET SIDETITLES ON

The SHOW Command

The SHOW command displays the current Data Definition Language (DDL) of a
database object (e.g., Table, View, Macro, Trigger, Join Index or Stored Procedure).
The SHOW command is used primarily to see how an object was created.

Sample Show Commands

Command Returns
CREATE TABLE
SHOW TABLE tablename;
statement
CREATE VIEW
SHOW VIEW viewname;
statement
CREATE MACRO
SHOW MACRO macroname;
statement

BTEQ also has a SHOW command (.SHOW CONTROL) which is different from the SQL
SHOW command. It provides information on formatting and display settings for the
current BTEQ session.

The SHOW TABLE Command

The SHOW TABLE command seen here returns the CREATE TABLE statement that was
used to create the employee table. To perform a SHOW TABLE, the user must have a
privilege on either the table itself or the containing database.

CREATE SET TABLE CUSTOMER_SERVICE.employee
,FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
employee_number INTEGER,
manager_employee_number INTEGER,
department_number INTEGER,
job_code INTEGER,
last_name CHAR(20) CHARACTER SET LATIN NOT CASESPECIFIC NOT NULL,
first_name VARCHAR(30) CHARACTER SET LATIN NOT CASESPECIFIC NOT NULL,
hire_date DATE NOT NULL,
birthdate DATE NOT NULL,
salary_amount DECIMAL(10,2) NOT NULL) UNIQUE PRIMARY INDEX
(employee_number);

Note: If a table is subsequently altered after it has been created, the SHOW command
will always reflect the most current alterations.

The SHOW VIEW Command

The SHOW VIEW command shows you the CREATE VIEW statement used to create a
view:

SHOW VIEW dept;
Result

CREATE VIEW dept
(dept_num
,dept_name
,budget
,manager)
AS
SELECT
department_number
,department_name
,budget_amount
FROM CUSTOMER_SERVICE.department;

The view may be accessed instead of the table:

SELECT * FROM dept;

Result
dept_num dept_name budget manager

--------- ----------- -------- ---------
301 research & development 46560000 1019
302 product planning 22600000 1016
501 marketing sales 80050000 1017
403 education 93200000 1005
402 software support 30800000 1011
401 customer support 98230000 1003
201 technical operations 29380000 1025

The SHOW Macro Command

The SHOW MACRO command shows you the statement used to create a macro:

SHOW MACRO get_depts;

Result

CREATE MACRO get_depts
AS (SELECT department_number
,department_name
,budget_amount
FROM department;
);

The EXPLAIN Command

The EXPLAIN function looks at a SQL request and responds in English how the
optimizer plans to execute it. It does not actually execute the SQL statement however
it is a good way to see what database resources will be used in processing your
request.

For instance, if you see that your request will force a full-table scan on a very large
table or cause a Cartesian Product Join, you may decide to re-write a request so that it
executes more efficiently.

EXPLAIN provides a wealth of information, including the following:

1. Which indexes if any will be used in the query.
2. Whether individual steps within the query may execute concurrently (i.e.
parallel steps).
3. An estimate of the number of rows which will be processed.
4. An estimate of the cost of the query (in time increments).

EXPLAIN SELECT * FROM department;

*** Query completed. Ten rows found. One column returned.

Explanation

1. First, we lock a distinct CUSTOMER_SERVICE."pseudo table" for read on a
RowHash to prevent global deadlock for CUSTOMER_SERVICE.department.
2. Next, we lock CUSTOMER_SERVICE.department for read.
3. We do an all-AMPs RETRIEVE step from CUSTOMER_SERVICE.department by way
of an all-rows scan with no residual conditions into Spool 1, which is built
locally on the AMPs. The size of Spool 1 is estimated with low confidence to be 4
rows. The estimated time for this step is 0.15 seconds.
4. Finally, we send out an END TRANSACTION step to all AMPs involved in
processing the request.
The contents of Spool 1 are sent back to the user as the result of statement 1.
The total estimated time is 0.15 seconds.

Lab
For this set of lab questions you will need information from the Database Info
document.

To start the online labs, click on the Telnet button in the lower left hand screen of the
course. Two windows will pop-up: a BTEQ Instruction Screen and your Telnet
Window. Sometimes the BTEQ Instructions get hidden behind the Telnet Window.
You will need these instructions to log on to Teradata.

A. Use the HELP DATABASE command to find all tables, views, and macros names
in the CS_Views database. What kind of objects do you find there? Do a
similar HELP command on the Customer_Service database. What kind of
objects do you find there?
B. To see the names of the columns in the department table, use the appropriate
HELP command. (Since the table is in the Customer_Service database, not
your default database, you'll have to qualify the table name with the database
name.) This is the command you may wish to use in the future to research
data names.
C. In Lab A, you may have noticed that the CS_Views database includes a view
called emp. SHOW that view. Notice the list of short names the emp view
uses in place of full column names. To save typing, you may use the emp
view with the shortened names in place of the employee table in any labs
throughout this course. (All lab solutions shown in this book use the employee
table in Customer_Service.)
D. Modify Lab A.1 from the previous module to cause the answer set to appear in
department name sequence. To find out how Teradata plans to handle this
request, submit it with EXPLAIN in front of it.
E. Use the appropriate SHOW command to see the table definition of the
employee_phone table in the Customer Service database.

F. Use the appropriate HELP command to see what kinds of indexes exist on the
customer table. To get information about your session, use another HELP
command. Change the display settings for sidetitles and foldline to better view
the session information. Be sure to reset display attributes once you have seen
results.
G. Change your current database setting to Customer_Service using the
DATABASE command. Try to do a SELECT of all columns and rows in the emp
view. Does it work? If not, how can you make it work?

Lab Answer A

HELP DATABASE cs_views;

*** Help information returned. 15 rows found.
Table/View/Macro name Kind Comment
agent_sales V ?
contact V ?
customer V ?
daily_sales V ?
department V ?
emp V ?
employee V ?
employee_phone V ?
jan_sales V ?
job V ?
location V ?
location_employee V ?
location_phone V ?
repair_time V ?
sales_table V ?

HELP DATABASE customer_service;

Table/View/Macro name Kind Comment
agent_sales T ?
contact T ?
customer T ?
daily_sales T ?
department T ?
employee T ?
employee_phone T ?
jan_sales T ?
job T ?
location T ?
location_employee T ?
location_phone T ?

repair_time T ?
sales_table T ?

Lab Answer B

HELP TABLE customer_service.department;


Column Name Type Comment
------------------------------ ---- -----------
department_number I2 ?
department_name CF ?
budget_amount D ?
manager_employee_number I ?

Lab Answer C

SHOW VIEW cs_views.emp;

*** Text of DDL statement returned.
CREATE VIEW emp
(emp
,mgr
,dept
,job
,last
,first
,hire
,birth
,sal)
AS
SELECT
employee_number
,department_number
,job_code
,last_name
,first_name
,hire_date
,birthdate

,salary_amount
FROM CUSTOMER_SERVICE.employee;

Lab Answer D

EXPLAIN SELECT * FROM customer_service.department ORDER BY
department_name ;

*** Help information returned. 11 rows found. Explanation

1. First, we lock a distinct customer_service."pseudo table" for
read on a RowHash to prevent global deadlock for
customer_service.department.

2. Next, we lock customer_service.department for read.

3. We do an all-AMPs RETRIEVE step from
customer_service.department by way of an all-rows scan with no
residual conditions into Spool 1, which is built locally on the
AMPs. Then we do a SORT to order Spool 1 by the sort key in
spool field1. The size of Spool 1 is estimated with low
confidence to be 12 rows. The estimated time for this step is
0.15 seconds.

4. Finally, we send out an END TRANSACTION step to all AMPs
involved in processing the request.
-> The contents of Spool 1 are sent back to the user as the
result of statement 1. The total estimated time is 0.15 seconds.

Lab Answer E

SHOW TABLE Customer_Service.employee_phone;

*** Text of DDL statement returned.
CREATE TABLE customer_service.employee_phone ,FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
employee_number INTEGER NOT NULL,
area_code SMALLINT NOT NULL,
phone INTEGER NOT NULL,
extension INTEGER,
comment_line CHAR(72) CHARACTER SET LATIN NOT
CASESPECIFIC)

PRIMARY INDEX( employee_number )
;

Lab Answer F

HELP INDEX Customer_Service.customer;

*** Help information returned. One row.
Primary or
Unique Secondary Column Names
Y P customer_number

.SET SIDETITLES ON
.SET FOLDLINE ON
HELP SESSION;
User Name tdxxx
Account Name $M_P0623_&D
Logon Date 00/11/29
Logon Time 11:52:18
Current DataBase tdxxx
Collation ASCII
Character Set ASCII
Transaction Semantics Teradata
Current DateForm IntegerDate
Session Time Zone 00:00
Default Character Type LATIN
Export Latin 1
Export Unicode 1
Export Unicode Adjust 0
Export KanjiSJIS 1
Export Graphic 0
Default Date Format None

.SET SIDETITLES OFF
.SET FOLDLINE OFF

Lab Answer G


SELECT * FROM emp;

(Fails because the emp view is not in database customer_service. To
make it work, fully qualify the view name.)

SELECT * FROM CS_Views.emp;

(You may also change the default database.)

DATABASE CS_Views;

SELECT * FROM emp;

Logical and Conditional Expressions Module 5

Objectives

Combine the following types of operators into logical expressions:
 comparison operators
 [NOT] IN
 IS [NOT] NULL
 LIKE
Form expressions involving NULL values.
Qualify a range of values.
Search for a partial string within a string expression.
Combine multiple logical expressions into a conditional expression using
AND and OR.

Logical Operators

Operators are symbols or words that cause an 'operation' to occur on one or more
elements called 'operands'.

Logical expressions combine operands and operators to produce a Boolean
(true/false) result. Logical expressions can be combined into conditional
expressions which are used in the WHERE clause of a SELECT statement.

Types of Operators in Logical Expressions

Operator Syntax Meaning
= equal
<> not equal
> greater than

< less than
>= greater than or equal to
<= less than or equal to
BETWEEN <a> AND inclusive range
[NOT] IN <expression> is in a list
or
<expression> is not in a list
IS [NOT] NULL <expression> is null
or
<expression> is not null
[NOT] EXISTS* table contains at least 1 row
or
table contains no rows
LIKE partial string operator

The EXISTS operator is covered in the Teradata Advanced SQL course.

BETWEEN -- Numeric Range Testing

To locate rows for which a numeric column is within a range of values, use the
BETWEEN <a> AND operator. Specify the upper and lower range of values that
qualify the row.

The BETWEEN operator looks for values between the given lower limit <a> and
given upper limit as well as any values that equal either <a> or (i.e.,
BETWEEN is inclusive.)

Example

Select the name and the employee's manager number for all employees whose job
codes are in the 430000 range.

SELECT first_name
,last_name
FROM employee
WHERE job_code BETWEEN 430000 AND 439999;

An alternative syntax is shown below:

SELECT first_name
,last_name
FROM employee
WHERE job_code >= 430000
AND job_code <= 439999;

first_name last_name manager_employee_number
----------- ----------- ------------------------------
Loretta Ryan 801
Armando Villegas 1005

BETWEEN -- Character Range Testing

Use the BETWEEN <a> AND operator to locate rows for which a character column
is within a range of values. Specify the upper and lower range of values that qualify
the row. BETWEEN will select those values which are greater than or equal to <a> and
less or equal to . (BETWEEN is inclusive.)

SELECT last_name
FROM employee
WHERE last_name BETWEEN 'r' AND 's';

last_name
------------
Ryan

Note: 'Stein' is not included because 'S_____' sorts lower than 'Stein'. (Teradata is
not case-sensitive by default.)

Set Operator IN
Use the IN operator as shorthand when multiple values are to be tested. Select the
name and department for all employees in either department 401 or 403. This query
may also be written using the OR operator which we shall see shortly.
SELECT first_name
,last_name
,department_number
FROM employee
WHERE department_number IN (401, 403);

first_name last_name department_number
----------- ----------- ---------------------

Darlene Johnson 401
Loretta Ryan 403
Armando Villegas 403
James Trader 401

Set Operator NOT IN

Use the NOT IN operator to locate rows for which a column does not match any of a
set of values. Specify the set of values which disqualifies the row.

SELECT first_name
,last_name
,department_number
FROM employee
WHERE department_number NOT IN (401, 403) ;

----------- ----------- ---------------------
Carol Kanieski 301
John Stein 301

NOT IN vs. OR

NOT IN provides a shorthand version of a 'negative OR' request. The following is an
example using the OR operator for the query example given above.

Select the name and the department for all employees who are NOT members of
departments 401 and 403.

SELECT first_name
,last_name
,department_number
FROM employee
WHERE NOT (department_number=401
OR
department_number=403);

----------- ----------- ---------------------
Carol Kanieski 301
John Stein 301

NULL

The following are facts about nulls:

NULL is used to represent the absence of a data value.
NULL is not the same as having a value of zero or spaces.
NULL indicates that a data value is missing or unknown.
NULL in a comparison operation produces an unknown result.
When doing an ascending sort on a column with NULL, NULLs sort before
negative values (numeric) and before blank values (character).
To prohibit NULLs, a column must be defined as NOT NULL.
Null columns may be compressed to occupy zero row space.

Arithmetic and Comparison Operation on NULL

The following logic applies to operations on NULLs:

Col A Operation Col B Results
10 + NULL NULL
10 - NULL NULL
10 * NULL NULL
10 / NULL NULL
10 > NULL UNKNOWN

10 < NULL UNKNOWN
10 >= NULL UNKNOWN
10 <= NULL UNKNOWN
10 = NULL UNKNOWN
10 <> NULL UNKNOWN
NULL > NULL UNKNOWN
NULL < NULL UNKNOWN
NULL >= NULL UNKNOWN
NULL <= NULL UNKNOWN
NULL = NULL UNKNOWN
NULL <> NULL UNKNOWN

Using NULL in a Select

Use NULL in a SELECT statement, to define that a range of values either IS NULL or IS
NOT NULL.

The following table lists two employees with unknown telephone extensions:

To list employee numbers in this table with unknown extensions:

FROM employee_phone
WHERE extension IS NULL;
employee_number
--------------------
1025
1005

To list employee numbers of people with known extensions:

FROM employee_phone
WHERE extension IS NOT NULL;
employee_number
--------------------
1008
1013

LIKE Operator

The LIKE operator searches for patterns matching character data strings.

You must provide two parameters for the LIKE operator: a string expression to be searched
and a string pattern for which to search.

The string can contain specific characters, as well as the following "wildcards":

% (indicates zero or more character positions)
_ (indicates a single character position)

Here are some examples using the LIKE operator:

String pattern
Meaning:
example:
LIKE 'JO%' begins with 'JO'
LIKE '%JO%' contains 'JO' anywhere
LIKE '__HN' contains 'HN' in 3rd and 4th position
LIKE '%H_' contains 'H' in next to last position

LIKE Operator -- Case-Blind Comparison

Case-Sensitivity: ANSI vs. BTET session transaction mode

Case-sensitivity of string comparisons is handled differently in the two different session
transaction modes (ANSI or BTET). This can lead to different results for a comparison
when run from sessions with different transaction modes. To ensure consistent
behavior, either case-sensitive or case-blind compares, use the following:

UPPER or LOWER operators for case-blind comparisons
CASESPECIFIC operator for case-sensitive comparisons

Case-Blind Compare

The UPPER function converts a string to uppercase. Use the UPPER string function on
both strings being compared to ensure a case-blind comparison regardless of the
session transaction mode. The LOWER function may be similarly used.

The NOT CASESPECIFIC data attribute can also be used to force case-blind
compares, however it is not an ANSI-compliant operator.

Problem

Display the full name of employees whose last name contains the letter "r" followed by
the letter "a".

Teradata Mode Solution

SELECT first_name
,last_name
FROM employee
WHERE last_name LIKE '%ra%';

first_name last_name
------------------------------ --------------------
James Trader
Peter Rabbit
I.B. Trainer
Robert Crane
Larry Ratzlaff

Since we are in Teradata (BTET) mode, the default for comparisons is non-case-
specific. Thus, we could have also used LIKE '%Ra%' or LIKE '%RA%' and
produced the same result.

ANSI Mode Solution

SELECT first_name
,last_name
FROM employee
WHERE last_name LIKE '%ra%';

------------------------------ --------------------
James Trader
I.B. Trainer
Robert Crane

Since we are in ANSI mode, the default for comparisons is case-specific. Thus, we will
not pick up Ratzlaff or Rabbit, unless we use 'case blind' testing, seen in the next
example.

SELECT first_name
,last_name
FROM employee
WHERE LOWER(last_name) LIKE LOWER('%ra%');


------------------------------ --------------------
James Trader
Peter Rabbit
I.B. Trainer
Robert Crane
Larry Ratzlaff
By applying the LOWER function to each side of the comparison, all testing is done in
a 'case blind' mode. UPPER could have also been used. We could also have used LIKE
'%ra%' (NOT CASESPECIFIC) to produce this result, however this is not an ANSI
standard approach.

LIKE Operator - Case-Sensitive Comparison

Use the CASESPECIFIC data attribute on one or both of the string expressions being
compared to ensure a case-sensitive comparison, regardless of the session transaction
mode. CASESPECIFIC is a Teradata extension.

Problem
Display the full name of employees whose last name contains "Ra". This is a case-
sensitive test.

Teradata Mode Solution

SELECT first_name
,last_name
FROM employee
WHERE last_name (CASESPECIFIC) LIKE '%Ra%';

------------------------------ --------------------
Peter Rabbit
Larry Ratzlaff

The default comparison for Teradata mode is not case-specific.

Use of the Teradata extension (CASESPECIFIC) forces a case-specific comparison.

Because we used the case-specific designator, we don't get James Trader in our answer
set but only get answers that contain an uppercase "R". The name 'LaRaye' would have
also appeared in this answer set, if it existed in the table. Using LIKE 'Ra%' will return
only names that begin with "Ra".

ANSI Mode Solution

SELECT first_name
,last_name
FROM employee
WHERE last_name LIKE '%Ra%';

------------------------------ --------------------

Peter Rabbit
Larry Ratzlaff

The default comparison for ANSI mode is case-specific.

Use of the Teradata extension (CASESPECIFIC) is not required. This could have also
been submitted with LIKE 'Ra%' and produced the same result, however it would have
missed a name like 'LaRaye'.

LIKE Operator -- Using Quantifiers

To extend the pattern matching functions of the LIKE operator, use quantifiers.

There are three such quantifiers:

ANY — any single condition must be met (OR logic)
SOME — same as ANY
ALL — all conditions must be met (AND logic)

ANY and SOME are synonyms. Using LIKE ANY and LIKE SOME will give the same result.

Problem

Display the full name of all employees with both "E" and "S" in their last name.

Solution

SELECT first_name
,last_name
FROM employee
WHERE last_name LIKE ALL ('%E%', '%S%');
---------- ----------
John Stein
Carol Kanieski
Arnando Villegas

Problem

Display the full name of all employees with either an "E" or "S" in their last name.

Solution

SELECT first_name
,last_name
FROM employee
WHERE last_name LIKE ANY ('%E%', '%S%');
----------- -----------
John Stein
Carol Kanieski
Arnando Villegas
Darlene Johnson
James Trader

LIKE with ESCAPE Character

The "_" and "%" symbols are used as 'wildcards' in the string expression of the LIKE
construct. However, what if one of the wildcard symbols is in the expression you are
evaluating. For example, to search for the substring "95%", you must define an
ESCAPE character to instruct the Parser to treat the '%' as a non-wildcard character.

To Summarize:

The ESCAPE feature of LIKE lets wildcard characters be treated as non-
wildcards.
Characters following the escape character are not treated as wildcards.

Problem

List all objects defined in the Teradata Database Data Dictionary whose names contain
"_" (underscore) as the second character.

Solution

SELECT tablename
FROM dbc.tables
WHERE tablename LIKE '_Z_%' ESCAPE 'Z';

TableName
------------------------------
M_7_B
t_wt_erd1

Things To Notice

The defined escape character is the letter 'Z'.
The first "_" (underscore) seen represents a wildcard - i.e., any single arbitrary
character.
The "Z_" sequence tells the Parser that the second "_" (underscore) is treated as
a character, not as a wildcard.

When you define an ESCAPE character, any use of the ESCAPE character in the string
expression must be immediately followed by either the "_", "%", or the ESCAPE
character itself.

Assume the escape character is defined to be the letter 'G'.

LIKE 'G_' means the underscore is treated as an underscore, not as a wildcard.
LIKE 'G%' means the percent sign is treated as a percent sign, not as a wildcard.
LIKE 'GG' means the two consecutive 'G' characters should be treated as a single 'G',
not as an escape character.

Example

LIKE '%A%%AAA_' ESCAPE 'A'

Searches for the following pattern:
- any number of arbitrary characters, followed by
- the "%" single character, followed by
- any number of arbitrary characters, followed by
- the "A" single character, followed by
- the "_" single character, which is the last character in the string.

Logical Operator -- AND

Logical operators AND, OR and NOT allow you to specify complex conditional expressions
by combining one or more logical expressions.

Logical Operator AND

The logical operator AND combines two expressions, both of which must be true in a
given record for them to be included in the result set.

Boolean Logic Table
True AND True = True
False AND True = False
True AND False = False
False AND False = False

True OR True = True
True OR False = True
False OR True = True
False OR False = False

NOT True = False
NOT false = True

Problem

Display the name and employee number of employees in department 403 who earn less
than $35,000 per year.

Solution

SELECT first_name
,last_name
,employee_number
FROM employee
WHERE salary_amount < 35000.00
AND department_number = 403 ;
first_name last_name employee_number
----------- ----------- --------------------
Loretta Ryan 1005

Logical Operator -- OR

The logical operator OR combines two expressions. At least one must be true in a given
record for it to be included in the result set.

Problem

Display the name and the employee number for employees who either earn less than
$35,000 annually or work in department 403.

Solution

SELECT first_name
,last_name
,employee_number
FROM employee
WHERE salary_amount < 35000.00
OR department_number = 403;

Result

---------- ---------- ----------------
Arnando Villegas 1007
Carol Kanieski 1008
Loretta Ryan 1005
John Stein 1006

Multiple AND . . . OR

You want to find all employees in either department 401 or department 403 whose
salaries are either under $35,000 or over $85,000.

SELECT last_name
,salary_amount
,department_number
FROM employee
WHERE (salary_amount < 35000
OR salary_amount > 85000)
AND (department_number = 401
OR department_number = 403) ;

Logical Operators -- Combinations

Operator Procedures

Parentheses can be used to force an evaluation order. In the presence of parentheses,
expressions are evaluated from the inner-most to outer-most set of parenthetical

expressions.

In the absence of parentheses, SQL uses the default precedence of the Boolean
operators. By default, NOT has higher precedence than AND which has higher precedence
than OR. Operators that have the same precedence level are evaluated from left to right
(e.g., multiple ORs or multiple ANDs).

If we remove the parentheses from the example above, our conditional expression gets
evaluated in a totally different order. If we were to use it in a query, it would yield
different results.

NOT has the highest precedence of the three operators.

Logical Operators -- Using Parentheses

Problem

Select the name, department number, and job code for employees in departments 401
or 403 who have job codes 412101 or 432101.

Solution

SELECT last_name
,department_number
,job_code
FROM employee
WHERE (department_number = 401
OR department_number = 403)
AND (job_code = 412101
OR job_code = 432101) ;

Result

last_name department_number job_code
----------- --------------------- ----------
Villegas 403 432101
Johnson 401 412101

If we accidentally left the parentheses out of our statement, would we get the same
results?

SELECT last_name
,department_number
,job_code
FROM employee
OR department_number = 403
AND job_code = 412101
OR job_code = 432101;
last_name department_number job_code
---------- --------------------- ---------
Villegas 403 432101

Johnson 401 412101
Trader 401 411100

Question
James Trader does not have either job code. Why was he selected?

Answer
Without parentheses, the default precedence causes the expression to be evaluated as
follows:

SELECT last_name
,department_number
,job_code
FROM employee
OR (department-number = 403
AND job_code = 412101)
OR job_code = 432101;

Remember, if any of the expressions that OR combines are true, the result is true. Since
James Trader is in department_number 401, that expression evaluates to true.
Therefore the row qualifies for output.

Multiple AND

Use multiple ANDs if you need to locate rows which meet all of two or more sets of
specific criteria.

For example, what happens if we take the previous example, and replace all the ORs
with ANDs?

SELECT last_name
,department_number
,job_code
FROM employee
AND department_number = 403
AND job_code = 432101;

No rows will be found. Why?

Answer

For a row to be displayed in this answer set, an employee would have to be in
department numbers 401 and 403. While we could conceive of an employee who
works in two departments, the employee table has only one field for department
number. There is no way that any row in this table can contain more than one
department number. This query never will return any rows. A more realistic example
follows.

Problem

Find all employees in department number 403 with job_code 432101 and a salary
greater than $25,000.

Solution

SELECT last_name
,department_number
,job_code
,salary
FROM employee
AND salary_amount > 25000.00 ;

Result

last_name department_number job_code salary_amount
----------- ---------------------- ---------- ----------------
Lombardo 403 432101 31000.00
Villegas 403 432101 49700.00
Charles 403 432101 39500.00
Hopkins 403 432101 37900.00
Brown 403 432101 43700.00

Logical NOT

Place the NOT operator in front of a conditional expression or in front of a comparison
operator if you need to locate rows which do not meet specific criteria.

Problem

Select the name and employee number of employees NOT in department 301.

Solution for NOT Operator

SELECT first_name
,last_name
,employee_number
FROM employee
WHERE department_number NOT = 301;

Solution for NOT Condition

SELECT first_name
,last_name

,employee_number
FROM employee
WHERE NOT (department_number = 301);

Result (Note that both approaches return the same result.)

------------ ------------ --------------------
Arnando Villegas 1007
James Trader 1003
Loretta Ryan 1005
Darlene Johnson 1004
SQL Lab Databases Info Document:
Your assigned user-id has SELECT access to the ‗Customer_Service‘
and the ‗Student‘ databases. These databases are used for labs
during this SQL course. When selecting from tables, either set your
default database to Customer_Service, Student, or your own user-
assigned database (depending on the lab requirements) or
alternatively, qualify your table names to reflect the appropriate
database.
The following pages include table definitions for the
‗Customer_Service‘ database and the ‗Student‘ database.
You may want to print this document for reference throughout this
course.

‗Customer_Service‘ Table Definitions

CREATE SET TABLE agent_sales ,NO FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
agent_id INTEGER,
sales_amt INTEGER)
UNIQUE PRIMARY INDEX ( agent_id );
--
CREATE TABLE clob_files
(Id INTEGER NOT NULL,
text_file CLOB(10000))
UNIQUE PRIMARY INDEX ( Id );
--
CREATE TABLE contact, FALLBACK
(contact_number INTEGER
,contact_name CHAR(30) NOT NULL
,area_code SMALLINT NOT NULL
,phone INTEGER NOT NULL
,extension INTEGER
,last_call_date DATE NOT NULL)
UNIQUE PRIMARY INDEX (contact_number);
--
CREATE TABLE customer, FALLBACK

(customer_number INTEGER
,customer_name CHAR(30) NOT NULL
,parent_customer_number INTEGER
,sales_employee_number INTEGER
)
UNIQUE PRIMARY INDEX (customer_number);
--
CREATE SET TABLE daily_sales
,NO FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
itemid INTEGER,
salesdate DATE FORMAT 'YY/MM/DD',
sales DECIMAL(9,2))
PRIMARY INDEX ( itemid );

--
CREATE SET TABLE daily_sales_2004
,NO FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
itemid INTEGER,
sales DECIMAL(9,2))

--
CREATE TABLE department, FALLBACK
(department_number SMALLINT
,department_name CHAR(30) NOT NULL
,budget_amount DECIMAL(10,2)
,manager_employee_number INTEGER
)
UNIQUE PRIMARY INDEX (department_number)
,UNIQUE INDEX (department_name);
--
CREATE TABLE employee, FALLBACK
(employee_number INTEGER
,manager_employee_number INTEGER
,department_number INTEGER
,job_code INTEGER
,last_name CHAR(20) NOT NULL
,first_name VARCHAR(30) NOT NULL
,hire_date DATE NOT NULL
,birthdate DATE NOT NULL
,salary_amount DECIMAL(10,2) NOT NULL
)
UNIQUE PRIMARY INDEX (employee_number);
--
CREATE TABLE employee_phone, FALLBACK
(employee_number INTEGER NOT NULL

,extension INTEGER
,comment_line CHAR(72)
)
PRIMARY INDEX (employee_number);
--
CREATE SET TABLE Jan_sales
,NO FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
itemid INTEGER,
sales DECIMAL(9,2))

--
CREATE TABLE job, FALLBACK
(job_code INTEGER
,description VARCHAR(40) NOT NULL
,hourly_billing_rate DECIMAL(6,2)
,hourly_cost_rate DECIMAL(6,2)
)
UNIQUE PRIMARY INDEX (job_code)
,UNIQUE INDEX (description);
--
CREATE TABLE location, FALLBACK
(location_number INTEGER
,customer_number INTEGER NOT NULL
,first_address_line CHAR(30) NOT NULL
,city VARCHAR(30) NOT NULL
,state CHAR(15) NOT NULL
,zip_code INTEGER NOT NULL
,second_address_line CHAR(30)
,third_address_line CHAR(30)
)
PRIMARY INDEX (customer_number);
--
CREATE TABLE location_employee, FALLBACK
(location_number INTEGER NOT NULL
,employee_number INTEGER NOT NULL
)
PRIMARY INDEX (employee_number);
--
CREATE TABLE location_phone, FALLBACK
(location_number INTEGER
,extension INTEGER
,description VARCHAR(40) NOT NULL
,comment_line LONG VARCHAR
)

PRIMARY INDEX (location_number);

--
CREATE TABLE phonelist
( LastName CHAR(20),
FirstName CHAR(20),
Number CHAR(12) NOT NULL,
Photo BLOB(10000))
UNIQUE PRIMARY INDEX ( Number );

--
CREATE TABLE repair_time
( serial_number INTEGER
,product_desc CHAR(8)
,start_time TIMESTAMP(0)
,end_time TIMESTAMP(0))
UNIQUE PRIMARY INDEX
(serial_number);

--
CREATE SET TABLE salestbl
,NO FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
storeid INTEGER,
prodid CHAR(1),
sales DECIMAL(9,2))
PRIMARY INDEX ( storeid );

‗Student‘ Database Table Definitions

CREATE TABLE city ,NO FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
cityname CHAR(15) NOT CASESPECIFIC,
citystate CHAR(2) NOT CASESPECIFIC,
citypop INTEGER)
PRIMARY INDEX ( cityname );

CREATE TABLE customers ,NO FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
cust_id integer not null
,cust_name char(15)
,cust_addr char(25) compress)
PRIMARY INDEX ( cust_id);

CREATE TABLE orders ,NO FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
order_id INTEGER NOT NULL
,order_date DATE FORMAT 'YYYY-MM-DD'
,cust_id INTEGER
,order_status CHAR(1))
UNIQUE PRIMARY INDEX ( order_id );

CREATE TABLE state ,NO FALLBACK ,
NO BEFORE JOURNAL,
NO AFTER JOURNAL
(
stateid CHAR(2) NOT CASESPECIFIC NOT NULL,
statename CHAR(15) NOT CASESPECIFIC,
statepop INTEGER NOT NULL,
statecapitol CHAR(15) NOT CASESPECIFIC)
PRIMARY INDEX ( stateid );

Lab


To start the online labs, click on the Telnet button in the lower left hand screen of the course. Two
windows will pop-up: a BTEQ Instruction Screen and your Telnet Window.

Sometimes the BTEQ Instructions get hidden behind the Telnet Window. You will need these
instructions to log on to Teradata.

Be sure to change your default database to the Customer_Service database in order to run these
labs.

A. Management needs a list with employee number, last name, salary and job code of all
employees earning between $40,001 and $50,000. Produce this report using the comparison
operators and sort by last name.

Modify the query to use the BETWEEN operator and sort by salary descending.

B. Management requests a report of all employees in departments 501, 301, and 201 who earn
more than $30,000. Show employee number, department number, and salary. Sort by
department number and salary amount within department.
C. Display location number, area code, phone number, extension, and description from the
location_phone table if the description contains the string ‘manager'. Sort by location
number.
D. List customers from the customer table identified by:
1. An unknown parent customer number; and
2. A known sales employee number.

Display all columns except parent customer number. Order results by customer number.

E. Create a report that lists all location numbers in area code 415 not dedicated to any manager.
Include all columns except comment and extension. Sequence by phone number.
F. List all job codes in the 400000 series that are management and all Analyst positions regardless
of job code value. List job code and description for the selected rows. Sort by description.
Submit again using EXPLAIN to look at how the Teradata RDBMS handled this request.
G. List the location numbers in area codes 415 or 617 which have no phone extensions. Order by
area code and phone number. Include all columns of the table except for description and
comment line columns. Notice how NULLs appear in your output.

Lab Answer A

,last_name
,salary_amount
,job_code
FROM employee
WHERE salary_amount >= 40001
AND salary_amount <= 50000
ORDER BY last_name
;


employee_number last_name salary_amount job_code
1024 Brown 43700.00 432101
1002 Brown 43100.00 413201
1010 Rogers 46000.00 412101
1007 Villegas 49700.00 432101
,last_name
,salary_amount
,job_code
FROM employee
WHERE salary_amount BETWEEN 40001 AND 50000
ORDER BY salary_amount DESC
;


employee_number last_name salary_amount job_code
1007 Villegas 49700.00 432101

1010 Rogers 46000.00 412101
1024 Brown 43700.00 432101
1002 Brown 43100.00 413201

Lab Answer B

,department_number
,salary_amount
FROM employee
WHERE salary_amount > 30000
AND department_number IN (501,301,201)
ORDER BY department_number
,salary_amount
;


employee_number department_number salary_amount
1025 201 34700.00
1021 201 38750.00
1019 301 57700.00
1015 501 53625.00
1018 501 54000.00
1017 501 66000.00

Lab Answer C

SELECT location_number
,area_code
,phone
,extension
,description
FROM location_phone
WHERE description LIKE '%Manager%'
ORDER BY location_number
;


location_number area_code phone extension description
5000001 415 4491225 ? System Manager
14000020 312 5692136 ? System Manager

22000013 617 7562918 ? System Manager
31000004 609 5591011 224 System Manager
33000003 212 7232121 ? System Manager

Lab Answer D

SELECT customer_number
,customer_name
,sales_employee_number
FROM customer
WHERE parent_customer_number IS NULL
AND sales_employee_number IS NOT NULL
ORDER BY 1
;

*** Query completed. 14 rows found. 3 columns
returned.
customer_number customer_name
sales_employee_number
-------------- ---------------------------- -
----------------------
1 A to Z Communications, Inc.
1015
3 First American Bank
1023
5 Federal Bureau of Rules
1018
6 Liberty Tours
1023
7 Cream of the Crop
1018
8 Colby Co.
1018
9 More Data Enterprise
1023
10 Graduates Job Service
1015
11 Hotel California
1015
12 Cheap Rentals
1018
14 Metro Savings
1018
15 Cates Modeling
1015
17 East Coast Dating Service
1023
18 Wall Street Connection
1023

Lab Answer E

,area_code
,phone
,description
FROM location_phone
WHERE area_code = 415
AND description NOT LIKE '%Manager%'
ORDER BY phone
;

returned.

location_number area_code phone description
--------------- --------- ----------- -------------
5000010 415 2412021 Alice Hamm
5000011 415 3563560 J.R. Stern
5000001 415 4491221 FEs office
5000001 415 4491244 Secretary
5000019 415 6567000 Receptionist
5000002 415 9237892 Receptionist

Lab Answer F

SELECT job_code
,description
FROM job
WHERE (job_code BETWEEN 400000 AND 499999
AND description LIKE '%manager%')
OR (description LIKE '%analyst%')
ORDER BY description
;


job_code description
----------- -----------------------------
411100 Manager - Customer Support
431100 Manager - Education
421100 Manager - Software Support
422101 Software Analyst
222101 System Analyst
412103 System Support Analyst

Note: EXPLAIN text varies depending on optimizer path.

Lab Answer G

,area_code
,phone
,extension
FROM location_phone
WHERE extension IS NULL
AND area_code IN (415,617)
ORDER BY area_code
,phone
;

returned.

location_number area_code phone extension
--------------- --------- ----------- -----------
5000010 415 2412021 ?
5000011 415 3563560 ?
5000001 415 4491221 ?
5000001 415 4491225 ?
5000001 415 4491244 ?
5000019 415 6567000 ?
5000002 415 9237892 ?
22000013 617 7562918 ?
22000013 617 7567676 ?

Data Types and Conversions Module:- 6

Objectives


Define the data type for a column in a table.
Compute values using arithmetic functions and operators.
Convert data from one type to another.
Manipulate the DATE data type.

Data Types

Every column in a row is associated with a data type that defines the kind of values it
accepts. These data types are associated with the fields when the table is created.
Data types fall into one of the four categories shown below:

Data Type Holds
Character data Character Strings
Byte data Binary Data Strings

Numeric data Numbers
Dates,Times,Timestamps,Time Intervals
(Note: Time, Timestamps and Intervals
Date/Time data
are covered in the Teradata SQL
Advanced course)

Character Data

There are two data types for holding character data:

CHAR - has fixed-length character strings.
VARCHAR - has variable-length character strings.

In both cases, the maximum string length is 64,000 characters. String size is specified
in parentheses after the keyword CHAR or VARCHAR as in CHAR(20) or VARCHAR(20).
There are subtle differences between the two.

In the case of CHAR, if you insert a character string less than the specified size (20 in
the above example), the system will append and store trailing blanks as needed to
expand the string to the specified length. The size specified on a VARCHAR field
represents a maximum length. The system will not pad the contents with trailing
blanks. (It will use two extra bytes to store the length internally however.)

When you know that data will always be a specific length (e.g., a Mail Stop that is a
four-character length) use CHAR. You save the two bytes that VARCHAR would use to
store the length. When data does not have a fixed length (e.g., last names), VARCHAR
makes more efficient use of the space, because it does not pad values with trailing
blanks.

Character Data Description Example
CHAR (size) Fixed length string last_name CHAR(20)
Max: 64,000 characters
Sample contents:
'Ryan__________'
VARCHAR (size) Variable length string first_name VARCHAR(30)
CHAR VARYING (size) Max: 64,000 characters
CHARACTER VARYING Sample contents:
(size) 'Loretta'
LONG VARCHAR Equivalent to
VARCHAR (64000)

Note: VARCHAR(size), CHAR VARYING(size), and CHARACTER VARYING(size) are all
equivalent synonyms.

LONG VARCHAR is equivalent to a maximum VARCHAR.

Character strings may be defined using any one of the following character sets:

Character Set Max Length
Latin 64,000 (English language default)
Kanji1 64,000
KanjiSJIS 64,000
Unicode 32,000 (two bytes per character)
Graphic 32,000 (two bytes per character)

Examples

first_name VARCHAR(30) CHARACTER SET LATIN

image_abc CHAR(32000) CHARACTER SET GRAPHIC

Byte Data

Teradata supports two data types for holding binary data:

BYTE.
VARBYTE.

BYTE is for fixed length binary strings. VARBYTE is for variable length binary strings.
These data types are used for storing binary objects such as digital images,
executable objects, flat files, etc.

Byte Data Description

BYTE (size) Fixed length
Binary string
Default: (1)
Max: 64,000 bytes

VARBYTE (size) Variable length
Binary string
Default: (1)
Max: 64,000 bytes

Note: BYTE columns are not covertible to other data types.

Numeric Data

The following numeric data types are available:

Data Type Description Examples
BYTEINT* Whole number basket_count
Range -128 to 127 BYTEINT
Storage: 1 byte +125
SMALLINT Whole number area_code
Range: -32,768 to 32,767 SMALLINT
Storage: 2 bytes +00213 (up to 5 digits)
INTEGER Whole number phone
Range: -2,147,483,648 to INTEGER
2,147,483,647 +0006495252 (up to 10 digits)
Storage: 4 bytes
BIGINT Whole number international_phone
Range ± BIGINT
9,233,372,036,854,775,80 +0000010807934842145 (up to 19 digits)
7
Storage: 8 bytes
DEC(m, n) 'm' is total number of digits. salary_amount
DECIMAL(m,n) (m <= 18) DEC (10,2)
NUMERIC(m,n 'n' is precision places to the +00035000.00
) right of decimal point.
(Small Decimal) Max Size =18 digits
Storage: 2 to 8 bytes
DEC(m, n) 'm' is total number of digits. sheet_thickness
DECIMAL(m,n) (18 < m <= 38) DEC (32,30)
NUMERIC(m,n 'n' is precision places to the +01.12349878279278758297727849782
) right of decimal point. 7
(Large Decimal) Max Size = 38 digits
Storage: 16 bytes
FLOAT Floating Point Format salary_factor
(IEEE) FLOAT
2x10-307 to 2x10+308 4.35400000000000E-001
Storage: 8 bytes

FLOAT Internally represented
[(precision)] as FLOAT
REAL Internally represented
as FLOAT
DOUBLE Internally represented
PRECISION as FLOAT

* Non-ANSI standard data type

Date Data

DATE represents a calendar date. It simplifies handling and formatting dates common to
business applications. DATE is stored as an integer, using the following formula:
(year - 1900) * 10000 + (month * 100) + day.

The DATE data type, shown here, is used in several forthcoming examples.

Data Type Description Examples
DATE Specially formatted integer: hire_date DATE
YYMMDD thru 1999 +0000990921
YYYMMDD from 2000 onward +0001000215

In the first example, the date being represented is September 21, 1999.
In the second example, the date being represented is February 15, 2000.

Note that the year is represented as an offset from the year 1900 in both cases. Note,
this is how the date is stored internally. How you see the date in a report depends on how
the date is formatted.

The recommended display format for DATE values is ‗YYYY-MM-DD‘. This format will avoid
problems that may occur from formats specifying only two digits for the year. This is a
significant issue as dates for the year 2000 and beyond are now commonly entered.

Example

2006-03-14 formatted as ‘YY-MM-DD’ displays ad 01-03-14, which is also the
representation for 1901-03-14.
2006-03-14 formatted as ‘YYYY-MM-DD’ displays as 2006-03-14, which is unambiguous.

Note: Formatting techniques for dates are discussed in the forthcoming module 'Output
Attributes'.

Arithmetic Operators

Teradata provides six binary arithmetic operators and two unary arithmetic operators.
They are defined in the tables below:

Binary Operators (require two operands)

Operator Definition
** exponentiation
* Multiply
/ Divide
MOD Modulos (remainders)
+ Add
- Subtract

Introduction to Teradata SQL

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