Teradata SQL

Features of Teradata

SQL

Module 14

Setting the Stage

After completing this module, you will be able to:

• State the purpose and function of the session

setting flags

• Recognize differences in transaction modes for

Teradata and ANSI

• Use the various HELP functions available

SQL Version 2 Differences

Teradata V2R2 (and later) consists of:

- All existing Teradata features from v1.

- ANSI compatible ways to perform many Teradata V1

features.

- Completely new features based on ANSI standard.

ANSI Teradata Inter.

Full

WITH BY

FORMAT

NAMED

CASE

AS

Macros

V2R2 allows for sessions to operate in either ...

- BTET (Teradata) mode

- ANSI mode

All syntax, both ANSI and Teradata extensions, is accepted

in either mode.

The same syntax might function differently in each mode.

Using ANSI mode to run existing V1 scripts will affect:

- Transaction protocol behavior

- Case sensitivity and collating sequences

- Certain data conversion and display functions

SQL Session Modes

Transaction mode setting

ANSI - uses ANSI mode (Commit mode)

BTET - uses standard Teradata mode

(Begin Txn - End Txn mode)

.SET SESSION TRANSACTION ANSI;

- requires COMMIT to end transaction

BTEQ Examples

.SET SESSION TRANSACTION BTET;

- requires BT to start explicit transaction

- requires ET to end explicit transaction

- requires neither for implicit transactions

Must be entered prior to LOGON.

To change session mode, must LOGOFF first.

Affects:

- Transaction protocol

- Default case sensitivities

- Data conversions

Transaction Modes - ANSI

ANSI mode:

A transaction is committed only by an explicit

COMMIT.

COMMIT WORK will commit the currently active Txn.

A rollback occurs when any of the following occur:

• ROLLBACK WORK - explicit rollback of

active Txn

• Session abort - rollback of active Txn

• SQL statement failure - rollback current

statement only

Transactions are by definition explicit.

Statement following a COMMIT automatically starts a

new Txn.

COMMIT is required immediately following any DDL.

Locks are accumulated until a COMMIT is issued.

.SET SESSION TRANSACTION ANSI;

Transaction Modes - Teradata

BTET mode:

A transaction is by definition implicit.

Each request is an implicit transaction.

BEGIN and END TRANSACTION are used to create

larger transactions out of individual requests.

BT begins an explicit Txn.

ET commits the currently active Txn.

A rollback occurs when any of the following occur:

• ROLLBACK WORK - explicit rollback of

active Txn

• Session abort - rollback of active Txn

• SQL statement failure - rollback of active Txn

Locks are accumulated following a BT until an ET is

issued.

.SET SESSION TRANSACTION BTET;

Transaction Examples

ANSI Mode

Upd A

Upd B

COMMIT

(both commit)

Upd A

Upd B (fails)

COMMIT

(A commits)

Upd A

Upd B

ROLLBACK

(both rollback)

Upd A

Upd B

LOGOFF

(both rollback)

BTET Mode

(explicit)

BT

Upd A

Upd B

ET (both commit)

BT

Upd A

Upd B (fails)

(both rollback)

BT

Upd A

Upd B

ROLLBACK

(both rollback)

BT

Upd A

Upd B

LOGOFF

(both rollback)

BTET Mode

(implicit)

Upd A (A commits)

Upd B (B commits)

Upd A (A commits)

Upd B (fails)

(rollback B)

(No explicit ROLLBACK

in implicit Txn)

Upd A (A commits)

Upd B (B commits)

LOGOFF

BTEQ .SHOW Command

[SET] FOLDLINE = OFF ALL

[SET] FOOTING = NULL

[SET] FORMAT = OFF

[SET] FORMCHAR = 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] 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 = l5442

[SET] TITLEDASHES = ON for the normal report.

And, it is ON for results of WITH clause number: 1 2 3 4 5 6 7 8 9.

[SET] UNDERLINE = OFF ALL

[SET] WIDTH = 75

.LOGON XYZ,XYZ;

.SHOW CONTROL;

HELP SESSION Command

HELP SESSION;

*** Help information returned. One row.

*** Total elapsed time was 1 second.

User Name TUSER25

Account Name $M_9038_&L

Logon Date 00/06/16

Logon Time 15:14:04

Current DataBase TUSER25

Collation ASCII

Character Set ASCII

Transaction Semantics Teradata

Current DateForm IntegerDate

Session Time Zone 00:00

Default Character Type LATIN

Note: To produce this format, use BTEQ settings:

.SET SIDETITLES

.SET FOLDLINE

To return to the default settings:

.SET DEFAULTS

Online Syntax HELP

Provides help on multiple utilities.

Provides global command menu.

Provides individual command syntax.

HELP ‘utilityname utilitycommand’;

HELP ‘SQL command-name’;

‘ARCHIVE command-name’;

‘BULKLOAD command-name’;

‘DUMP command-name’;

‘FASTEXPORT command-name’;

‘FASTLOAD command-name’;

‘MULTILOAD command-name’;

‘PMPC command-name’;

‘TPCCONS command-name’;

HELP ‘SQL’;

HELP ‘SQL SELECT’;

HELP ‘SQL ALTER TABLE’;

Online Syntax help

HELP Examples

HELP 'SQL';

*** Query completed. 35 rows found. One column returned.


On-Line Help

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

DBS SQL COMMANDS:

ABORT ALTER TABLE BEGIN LOGGING

BEGIN TRANSACTION CHECKPOINT COLLECT STATISTICS

COMMIT COMMENT CREATE DATABASE

CREATE INDEX CREATE MACRO CREATE TABLE

CREATE USER CREATE VIEW DATABASE

DELETE DELETE DATABASE DELETE USER

DROP DATABASE DROP INDEX DROP MACRO

DROP TABLE DROP VIEW DROP STATISTICS

ECHO END LOGGING END TRANSACTION

EXECUTE EXPLAIN GIVE

GRANT GRANT LOGON HELP

: : :

HELP 'SQL UPDATE';

*** Query completed. 10 rows found. One column returned.


On-Line Help

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

UPD[ATE] tablename [ [AS] aname ] [ FROM tname [ [AS] aname] ]

[... ,tname [ [AS] aname ] ] ;

SET columnname = expr [ ... ,columnname = expr]

[ WHERE condition ]

[ ] ;

[ ALL ]

SELECT Statement ANSI Join Syntax

SELECT cname [, cname , …]

FROM tname [aname] [INNER]

LEFT [OUTER]

RIGHT [OUTER]

FULL [OUTER]

CROSS

JOIN tname [aname]

ON condition ;

Where:

cname Column or expression name

tname Table or view name

aname Alias for table or view name

condition Criteria for the join

INNER JOIN All matching rows

LEFT OUTER JOIN Table to the left is used to qualify,

table on the right has nulls when

rows do not match.

RIGHT OUTER JOIN Table to the right is used to qualify,

table on the left has nulls when

rows do not match.

FULL OUTER JOIN Both tables are used to qualify and

extended with nulls.

CROSS JOIN Cartesian product

With V2R2 (and later), Teradata supports the ANSI

join syntax and outer joins - details in Appendix B.

CASE Sensitivity Issues - Teradata

Storage As entered (default)

UPPERCASE

Comparisons UPPER, LOWER

CASESPECIFIC (CS)

NONCASESPECIFIC (NOT CS)

(Teradata default)

Teradata Rules - Column Attributes

SELECT first_name

, last_name

FROM employee

WHERE last_name

LIKE ‘%Ra%’;

first_name last_name

Robert Crane

James Trader

I.B. Trainer

Larry Ratzlaff

Peter Rabbit

SELECT first_name

, last_name

FROM employee

WHERE last_name(CS)

LIKE ‘%Ra%’;


Larry Ratzlaff

Peter Rabbit

Default (NOT CS) result (CS) result

CASE Sensitivity Issues - ANSI

SELECT first_name

, last_name

FROM employee

WHERE last_name

LIKE ‘%Ra%’;


Larry Ratzlaff

Peter Rabbit

SELECT first_name

, last_name

FROM employee

WHERE last_name(CS)

LIKE ‘%Ra%’;


Larry Ratzlaff

Peter Rabbit

Default (CS) result Explicit CS result

Storage None

(As entered is default)

Comparisons UPPER, LOWER

(Casespecific is default)

ANSI Rules - Column Attributes

Using ESCAPE with LIKE

SELECT test_num, comment

FROM test_results

WHERE comment LIKE ‘%95a%%’ ESCAPE ‘a’;

LIKE Wildcard rules

Underscore ‘_’ replaces one character.

Percent sign ‘%’ replaces zero to many characters.

ESCAPE permits use of ‘_’ or ‘%’ as part of string

search criteria.

ESCAPE rule

SELECT filename, filesize

FROM file_table

WHERE filename LIKE ‘%ANSIb_SQLb_%’ ESCAPE ‘b’;

test num comment

15365 Result is 95%

filename filesize

ANSI_SQL_QRY3 2068

Data Types

Teradata ANSI (Entry) equivalent

INTEGER INTEGER

SMALLINT SMALLINT

BYTEINT

DATE

TIME

TIME WITH ZONE

TIMESTAMP

TIMESTAMP WITH ZONE

FLOAT FLOAT

FLOAT REAL

FLOAT DOUBLE PRECISION

DECIMAL(n,m) DECIMAL(n,m)

DECIMAL(n,m) NUMERIC(n,m)

CHAR(n) CHAR(n)

VARCHAR(n)

CHAR VARYING(n)

LONG VARCHAR

BYTE(n)

VARBYTE(n)

GRAPHIC(n)

VARGRAPHIC(n)

LONG VARGRAPHIC

Table Level Attributes

CREATE MULTISET TABLE sales_period

DATABLOCKSIZE = 16384 BYTES

FREESPACE = 10 PERCENT

(period_num INT);

SET Don’t allow duplicate rows

MULTISET Allow duplicate rows (ANSI)

DATABLOCKSIZE

Maximum multi-row blocksize for table in:

BYTES Rounded to nearest sector (512)

KILOBYTES Increments of 1024

(or KBYTES)

MINIMUM DATABLOCKSIZE (6144)

MAXIMUM DATABLOCKSIZE (65024)

FREESPACE Percent of freespace to keep on

cylinder during loading operations

(0 - 75%)

Column Attributes

Attribute ANSI Teradata

UPPERCASE Yes

CASESPECIFIC Yes

FORMAT Yes

TITLE Yes

NAMED/AS Yes

COMPRESS Yes

COMPRESS NULL Yes

COMPRESS value Yes

WITH DEFAULT Yes

DEFAULT DATE Yes

DEFAULT TIME Yes

NOT NULL Yes Yes

DEFAULT value Yes Yes

DEFAULT USER Yes Yes

DEFAULT NULL Yes Yes

Primary Keys And Indexes (Review)

Primary key - one or more columns used to uniquely

identify the rows of a table (one per table).

Primary keys (PK) are used in conjunction with foreign

keys to define the important relationships in a

database.

PK’s are always unique and cannot be null.

PK’s are not known to the Teradata DBS as such.

PK’s are implemented as indexes by the Teradata DBS.

Primary index - one or more columns used to distribute

and locate the rows of a table (one per table).

Primary index(PI) choice will affect distribution, access

and thus performance.

Indexes (primary or secondary) may be used to enforce

uniqueness.

Indexes (primary or secondary) may be used to improve

access.

Indexes (primary or secondary) may be unique or non-

unique.

Primary Keys

Indexes

Creating Employee Table

With Constraints

CREATE TABLE employee ,FALLBACK ,

NO BEFORE JOURNAL,

NO AFTER JOURNAL

(

employee_number INTEGER NOT NULL

PRIMARY KEY,

manager_employee_number INTEGER

REFERENCES employee(employee_number),

department_number INTEGER

REFERENCES department(department_number),

job_code INTEGER

REFERENCES job(job_code),

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)

;

Primary Key column(s) must be defined NOT NULL.

Referenced columns must be defined as unique.

Up to 64 foreign keys may be defined on a table.

User must have REFERENCES right on referenced

table.

All constraints are unnamed.

All constraints are at the column level.

Show Table Constraints

Employee Table

SHOW TABLE employee;

CREATE SET TABLE employee ,FALLBACK ,

NO BEFORE JOURNAL,

NO AFTER JOURNAL

(

employee_number INTEGER NOT NULL,

manager_employee_number INTEGER,

department_number INTEGER NOT NULL,

job_code INTEGER,

last_name CHAR(20) NOT CASESPECIFIC NOT NULL,

first_name VARCHAR(30) NOT CASESPECIFIC NOT NULL,

hire_date DATE NOT NULL,

birthdate DATE NOT NULL,

salary_amount DECIMAL(10,2) NOT NULL,

FOREIGN KEY ( manager_employee_number )

REFERENCES employee ( employee_number ),

FOREIGN KEY ( department_number )

REFERENCES department( department_number),

FOREIGN KEY ( job_code )

REFERENCES job ( job_code )

)

UNIQUE PRIMARY INDEX ( employee_number );

Note: Primary key becomes the Primary index.

Altering Table Constraints

ALTER TABLE tablename

ADD CONSTRAINT constrname CHECK

ADD CONSTRAINT constrname UNIQUE

ADD CONSTRAINT constrname PRIMARY KEY

ADD CONSTRAINT constrname FOREIGN KEY

To add constraints to a table:


DROP CONSTRAINT constrname


MODIFY CONSTRAINT constrname

To modify existing constraints:

To drop constraints:

What is a Trigger?

A Trigger may be defined as:

• One or more stored SQL statements associated with a

table

• An event driven procedure attached to a table

• An object in a database, like tables, views and macros

Any of the following SQL statements may be applied to

triggers:

CREATE

DROP

SHOW

ALTER

RENAME

REPLACE

HELP

Triggers may not be used in conjunction with:

• The FastLoad utility

• The MultiLoad utility

• Updateable Cursors (Preprocessor environment)

DELETE DATABASE

DELETE USER

Both cause all triggers

to be dropped.

Privileges are required to create and drop triggers.

GRANT

REVOKE

CREATE

DROP TRIGGER

TRIGGERS

Temporary Table Choices

Derived Tables

• Local to the query (table and columns are

named within query)

• Incorporated into SQL query syntax (populated

in query via SELECT in FROM)

• Materialized in SPOOL - Spool rows are

discarded when query finishes

• No data dictionary involvement

• Commonly used with aggregation

Volatile Tables

• Local to a session - uses SPOOL space

• Uses CREATE VOLATILE TABLE syntax

• Discarded automatically at session end

• No data dictionary involvement

(Global) Temporary Tables

• Local to a session - uses TEMPORARY space

• Uses CREATE GLOBAL TEMPORARY TABLE

syntax

• Materialized instance of table discarded at

session end.

• Creates and keeps table definition in data

dictionary

Inserting Default Values

INSERT INTO tablename DEFAULT VALUES;

Will insert defined default values into each column.

If no default is defined, will insert a null.

If no default defined and null not allowed, insert will fail.

INSERT INTO test_tbl DEFAULT VALUES;

SELECT * FROM test_tbl;

CREATE TABLE test_tbl

(cola SMALLINT NOT NULL DEFAULT 22

,colb CHAR(1)

,colc DATE DEFAULT 1000101 FORMAT 'YYYY-MM-DD'

,cold DEC(3,2) NOT NULL WITH DEFAULT

,cole TIME(0) DEFAULT CURRENT_TIME

,colf INT DEFAULT TIME

,colg CHAR(8) DEFAULT USER);

cola colb colc cold cole colf colg

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

22 ? 2000-01-01 .00 11:14:14 111414 PED

INSERT INTO test_tbl DEFAULT VALUES;

SELECT * FROM test_tbl;

cola colb colc cold cole colf colg

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

22 ? 2000-01-01 .00 11:14:14 111414 PED

22 ? 2000-01-01 .00 11:14:37 111437 PED

Lab Environment

DBC

Accounts

Lab3_1_1

Lab3_1_2

Customer

Trans Accounts

Customer

Trans

T____01

Teradata_Factory

AU ____Students

Accounts

Customer

Trans

T____02

Accounts

Customer

Trans

T____xx

Note: ___ Instructor Initials

UNIX userids u____01

u____02

u____xx

Useful Teradata Commands in BTEQ:

.LOGON tpdid/username - logon to Teradata

HELP SESSION; - displays session information

HELP USER username; - lists objects owned by user

HELP ‘SQL sqlcommand’; - help for an SQL command

SHOW TABLE tablename; - shows table creation syntax

SELECT COUNT(*) FROM tname; - provides count of rows in table

DELETE tablename ALL; - deletes all rows in a table

DROP TABLE tablename; - drops table from the database

EXEC macroname; - executes a macro

.RUN FILE=filename - executes a file of BTEQ/SQL commands

.QUIT - exits BTEQ

Useful UNIX Commands:

ls -l - long listing of UNIX files)

pg (or more) filename - view contents of text file

vi (or vedit) filename - create or edit a text file

cp file1 file2 - copies file1 to file2

mv filename newfilename - renames a file

rm filename - delete a file

exit - exits UNIX

SELECT Statement Join Syntax

SELECT cname [, cname , …]

FROM tname [aname] [INNER]

LEFT [OUTER]

RIGHT [OUTER]

FULL [OUTER]

CROSS

JOIN tname [aname]

ON condition ;

Where:

cname Column or expression name

tname Table or view name

aname Alias for table or view name

condition Criteria for the join

INNER JOIN All matching rows

LEFT OUTER JOIN Table to the left is used to qualify,

table on the right has nulls when

rows do not match.

RIGHT OUTER JOIN Table to the right is used to qualify,

table on the left has nulls when

rows do not match.

FULL OUTER JOIN Both tables are used to qualify and

extended with nulls.

CROSS JOIN Cartesian product

Inner Joins

SELECT D.Department_Number AS Dept

,Department_Name

,Last_name

,E.Department_Number AS EmpDept

FROM Department D INNER JOIN

Employee E

ON E.Department_Number =

D.Department_Number;

An inner join returns an output row for each successful

match between the join tables.

Dept Department_Name Last_Name EmpDept

402 software support Crane 402

100 executive Trainer 100

501 marketing sales Runyon 501

301 research and development Stein 301

301 research and development Kanieski 301

Information about employees and their department names

where the employee’s department number matches the

existing departments.

No information about employees who have no department

number or an invalid department number.

No information about departments which have no

employees assigned to them.

Outer Joins

An outer join returns matching rows and non-

matching rows.

SELECT D.Department_Number AS Dept

,Department_Name

,Last_name

,E.Department_Number AS EmpDept

FROM Employee E FULL OUTER JOIN

Department D


D.Department_Number;

Dept Department_Name Last_Name EmpDept

600 new department ? ?

402 software support Crane 402

? ? James 111

501 marketing sales Runyon 501

301 research and development Kanieski 301

? ? Green ?

100 executive Trainer 100

301 research and development Stein 301

In addition to output from inner join:

Shows employees with null departments.

Shows employees with invalid departments.

Shows departments with no employees.

LEFT Outer Join Example

SELECT E.Department_Number

,Department_Name

,Last_Name

FROM Employee E LEFT OUTER JOIN

Department D


D.Department_Number

;

department_number department_name last_name

402 software support Crane

111 ? James

501 marketing and sales Runyon

301 research and develop Stein

? ? Green

100 executive Trainer

301 research and develop Kanieski


Shows employees with null departments.

Shows employees with invalid departments.

RIGHT Outer Join Example

SELECT D.Department_Number

,Department_Name

,Last_Name

FROM Employee E RIGHT OUTER JOIN

Department D


D.Department_Number

;

department_number department_name last_name

600 new department ?

402 software support Crane

100 executive Trainer

501 marketing sales Runyon

301 research and develop Stein

301 research and develop Kanieski


Shows departments with no employees.

Outer Joins of More Than Two Tables

Each JOIN must have an associated ON clause.

In joining more than two Tables in an outer join, the

ON clause needs to be placed appropriately so

that the join operation can be evaluated correctly.

SELECT last_name AS Employee

,department_name AS Dept

,description AS Job

FROM Department D RIGHT OUTER JOIN

Employee E

ON D.Department_Number =

E.Department_Number

LEFT OUTER JOIN

Job J

ON E.Job_Code = J.Job_Code

;

Returns all employees including:

employees with invalid departments

employees with null departments

employees with invalid job codes

employees with null job codes

ON Clause Placement

The placement of the ON clause in the SELECT is

important.

The rules are:

• The first ON clause (from left to right) is evaluated first.

• An ON clause applies to the immediately preceding

join operation.



,description AS Job

FROM Department D RIGHT OUTER JOIN

Employee E LEFT OUTER JOIN

Job J

ON E.Job_Code = J.Job_Code

ON D.Department_Number = E.Department_Number;



,description AS Job

FROM (Department D RIGHT OUTER JOIN

(Employee E LEFT OUTER JOIN

Job J

ON E.Job_Code = J.Job_Code )

ON D.Department_Number = E.Department_Number);

Using parenthesis can clarify the reading of the statement.

The same SELECT example could be written as:

Cross Joins

A cross join is a join that requires no join condition.

Cross joins are sometimes called product joins.

Each participating row of one table is joined with

each participating row of another table.

Cross join syntax does not allow an ON clause.

A WHERE clause may restrict which rows participate

from either table.

employee_number department_number

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

1008 501

1008 301

1008 402

1008 201

1008 302

1008 600

1008 401

1008 100

1008 403

SELECT e.employee_number

,d.department_number

FROM employee e CROSS JOIN

department d

WHERE e.employee_number = 1008;

One employee matched with nine departments

results in nine rows of output.

Output is not meaningful.

Cartesian Products

A completely unconstrained cross join is called a

‘Cartesian Product’.

Each row of one table is joined to each row of

another table.

A Cartesian product results from a CROSS JOIN

without a WHERE clause.

SELECT e.employee_number


FROM employee e CROSS JOIN

department d;

Each employee row (26) matched with each

department row (9) yields 234 rows of output.

An 8,000,000 row table and a 50,000 row table would

yield a 400,000,000,000 row answer set.

The output of a Cartesian product is rarely

meaningful.

Cartesian products can also result from an INNER

JOIN with improper aliasing or improper join

conditions.

SELECT employee.employee_number


FROM employee e INNER JOIN

department d

ON e.department_number = d.department_number;

Thank You!!!

Teradata SQL

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