34781 Cannon

Introduction to Teradata SQL

Gary Cannon

Sr. Consulting EngineerStrategic Warehousing and [email protected]

September 7, 2006

Teradata, a division of NCR -- Proprietary & Confidential, Do not distribute 2

Gary CannonEducation Specialist

Gary Cannon, joined NCR in June 1970. He worked in various IT related

positions through October 1997 when he joined Teradata Customer Education to teach UNIX and Teradata courses.

Gary presents the Introduction to Teradata, SQL, Application Utilities and Physical Database Design courses.


Agenda

Present an introduction to Teradata SQL

Identify many of the unique features of Teradata SQL


ANSI SQL Standards

• Three defined SQL standards:

SQL-89 (SQL 1)

SQL-92 (SQL 2)- Entry Level- Intermediate Level- Full Level

SQL-99 (SQL 3)- Core- Enhanced

• Teradata SQL is certified at the SQL-92 Entry level with some Intermediate, some Full and some SQL-99 Core features

• New Teradata SQL features are added using the ANSI SQL-99 standard


Object Names - Rules and Qualification

Creating Object Names: ANSI Teradata SQL

Legal Characters A-Z, 0 -9, _

(underscore) Same as ANSI, plus: a -z, #, $

First character A-Z Any except 0 -9

Last character Can’t be _ (Underscore)

Any

Length 18 characters 30 characters

Case sensitivity N/A No

• The syntax for qualifying an object name is:

[[ databasename. ] tablename. ] columnname columnname (unqualified) tablename.columnname (partially qualified) databasename.tablename.columnname (fully qualified)

• Comments are delimited by /* and */

SELECT * FROM table1 /* select all columns */;


Object Names - Case Sensitivity

• ANSI compliant object names and keywords are upper case only

• Teradata accepts mixed case object names and keywords

Example table:

CREATE TABLE Table1 ( Col1 INTEGER ,Col2 CHAR(10) ,Col3 SMALLINT) UNIQUE PRIMARY INDEX (Col1);

Example statements that are valid in Teradata:

SELECT COL1 FROM TABLE1;

SELECT Col1 FROM Table1;

SeLeCt COl1 From table1;

select col1 from table1;


Object Names - Double Quotes

SELECT * FROM table; *** Failure 3707 Syntax error, expected something like a name between the 'from' keyword and the 'table' keyword.

SELECT * FROM "table"; *** Failure 3807 Object 'table' does not exist.

SELECT * FROM table one; *** Failure 3707 Syntax error, expected something like a name between the 'from' keyword and the 'table' keyword.

SELECT * FROM "table one"; *** Failure 3807 Object 'table one' does not exist.

• Double quotes around an object name overrides naming rules

• Double quotes allow reserved words to be used as object names


SQL Command Abbreviations

BEGIN TRANSACTION BTEND TRANSACTION ET

CREATE MACRO CMCREATE TABLE CT

DELETE DELINSERT INSSELECT SELUPDATE UPD

• Several SQL Commands may be abbreviated in Teradata

SELECT command examples:

SELECT * FROM table1;

SEL * FROM table1;

SEL table1.*;


Built-In Functions

• Several system built-in functions are available in Teradata

ACCOUNT - contains the users account stringDATABASE - contains the current default databaseDATE - contains the current dateSESSION - contains the current session-idTIME - contains the current timeUSER - contains the user name

SELECT example:

SELECT ACCOUNT, DATABASE, DATE, SESSION, TIME, USER;

Account Database Date Session Time User--------- --------- ----------- -------- --------- -------$M_USR_&L USER01 2004/08/12 1756743 14:45:57 USER01

• Changing your default database

DATABASE new_database_name;


HELP Command

• The HELP Command provides information on database objects

Databases and Users:

HELP DATABASE databasename; HELP USER username;

Database Objects:

HELP TABLE tablename; HELP VIEW viewname; HELP MACRO macroname; HELP Database Example:

HELP DATABASE user01;

Table/View/Macro name Kind Comment --------------------- ---- ------------------------ Table1 T ? View1 V ? Macro1 M ?


HELP SESSION Command

• The HELP SESSION Command provides information about your session

HELP SESSION; (partial output)

User Name USER01Account Name $M_USR_&LLogon Date 04/08/12Logon Time 19:20:35Current DataBase USER01Collation ASCIICharacter Set ASCIITransaction Semantics TeradataCurrent DateForm IntegerDateSession Time Zone 00:00Default Character Type LATINExport Latin 1Export Unicode 1Export Unicode Adjust 0Export KanjiSJIS 1Export Graphic 0Default Date Format yyyy/mm/dd ...


HELP 'SQL' Command

HELP 'SQL'; (HELP 'SQL DELETE'; for DELETE syntax rules)

DBS SQL COMMANDS:ABORT ALTER FUNCTION ALTER PROCEDUREALTER TABLE ALTER TRIGGER BEGIN LOGGINGBEGIN QUERY LOGGING BEGIN TRANSACTION CALLCHECKPOINT COLLECT DEMOGRAPHICS COLLECT STATISTICSCOMMENT COMMIT CREATE DATABASECREATE FUNCTION CREATE HASH INDEX CREATE INDEXCREATE JOIN INDEX CREATE MACRO CREATE PROCEDURECREATE PROFILE CREATE ROLE CREATE TABLECREATE TRIGGER CREATE USER CREATE VIEW ...

DBS SQL FUNCTIONS:ABS ADD_MONTHS ACOSACOSH ASIN ASINHATAN ATANH ATAN2AVERAGE BYTES CAST ...

• The HELP 'SQL' Command provides information about SQL Commands


SHOW Command

• The SHOW Command provides information on how objects were created

Database Objects:

SHOW TABLE tablename; - returns the create table command

SHOW VIEW viewname; - returns the create view command SHOW MACRO macroname; - returns the create macro

command

Example SHOW TABLE:

SHOW TABLE table1; ---------------------------------------------------------- CREATE SET TABLE USER01.table1 ,NO FALLBACK , NO BEFORE JOURNAL, NO AFTER JOURNAL, CHECKSUM = DEFAULT ( col1 INTEGER, col2 CHAR(10) CHARACTER SET LATIN NOT CASESPECIFIC, col3 SMALLINT) UNIQUE PRIMARY INDEX ( col1 );


EXPLAIN Command

The EXPLAIN text provides: An English translation of the AMP steps A row count and time estimates for comparison only Which indexes, if any will be used Whether individual steps will process in parallel

EXPLAIN SELECT * FROM Table1;

Explanation 1) First, we lock a distinct USER01."pseudo table" for read on a RowHash to prevent global deadlock for USER01.table1. 2) Next, we lock USER01.table1 for read. 3) We do an all-AMPs RETRIEVE step from USER01.table1 by way of an all-rows scan with no residual conditions into Spool 1 (group_amps), which is built locally on the AMPs. The size of Spool 1 is estimated with low confidence to be 16 rows. The estimated time for this step is 0.56 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 0.56 seconds.


Equivalent Comparison Operators

OPERATOR EXTENSION = EQ

<> NE ^= NOT=

> GT

< LT

>= GE

<= LE


Case Sensitivity - Comparisons

• Teradata is not case sensitive on character comparisons

SELECT col2 FROM table2 WHERE col2 = 'abc';

col2----------aBcABCABcabc

• Use CASESPECIFIC (or CS) to force ANSI standard case sensitivity

SELECT col2FROM table2 WHERE col2 (CASESPECIFIC) = 'abc';

col2----------abc


Additional Data Types

DATA TYPE DEFINITION BYTE 1 to 64,000 bytes fixedVARBYTE 1 to 64,000 bytes variable

BYTEINT 1 byte ranging in value from -128 to +127

DATE 4 bytes stored as:

YYMMDD for dates 1999-12-31 and earlier or YYYMMDD for dates 2000-01-01 and beyond

((YEAR - 1900) * 10000) + (MONTH * 100) + DAY)

GRAPHIC 1 to 32,000 characters (each 2 bytes) fixedVARGRAPHIC 1 to 32,000 characters (each 2 bytes) variable

LONG VARCHAR same as VARCHAR(64000)


Calculator

• Teradata provides a built-in calculator

Calculation Result Comment

SELECT 2*250; 500 Simple multiplication

SELECT 1.01 + 2.2; 3.21 Uses greatest possible precision

SELECT 10/3.000; 3.333 Rounds off

SELECT 10/6.000; 1.667 Rounds up

• Teradata will display the order of evaluation

SELECT 3 * 5 + 6 / 3 - 8 * 2 + 3;

((((3*5)+(6/3))-(8*2))+3)------------------------- 4


ADD_MONTHS Function

Query Results

SELECT DATE; 01/08/07

ADD_MONTHSSELECT ADD_MONTHS (DATE, 2); 2001-10-07

SELECT ADD_MONTHS (DATE, 12*14); 2015-08-07

SELECT ADD_MONTHS (DATE, -11); 2000-09-07

ADD_MONTHS - literal dateSELECT ADD_MONTHS ('2001-07-31', 2); 2001-09-30

SELECT ADD_MONTHS ('2003-12-31', 2); 2004-02-29

SELECT ADD_MONTHS ('2003-12-31', 14); 2005-02-28

SELECT ADD_MONTHS('2004-01-31',1) AS "January 31 + 1 Month" ,ADD_MONTHS('2004-02-29',1) AS "February 29 + 1 Month";

January 31 + 1 Month February 29 + 1 Month -------------------- --------------------- 2004-02-29 2004-03-29


Data Conversion with CAST

SEL CAST(50500.75 AS INTEGER) AS "Truncated" ,CAST(50500.75 AS DECIMAL(6,0)) AS "Rounded";

Truncated Rounded----------- -------- 50500 50501.

SEL CAST(6.74 AS DECIMAL(2,1)) AS "Drop Precision" ,CAST(6.75 AS DECIMAL(2,1)) AS "Round Up" ,CAST(6.85 AS DECIMAL(2,1)) AS "Round Down to Even";

Drop Precision Round Up Round Down to Even-------------- -------- ------------------ 6.7 6.8 6.8

SEL 'Teradata'(char(4)) as "Truncate with CAST" ,'Teradata'(char(4),UPPERCASE) as "Truncate & UPPERCASE";

Truncate with CAST Truncate & UPPERCASE ------------------ ---------------------- Tera TERA


Questions?

Raise your virtual hand to let us know you have a question

Type your question in this box I am not clear about the use of triggers

I am not clear about the use of triggersJohn Q Public

Questions can be submitted at any time. We will answer questions using the text chat window at several scheduled breaks throughout the session.

Then Click Send

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Multiple Column Match Subquery

• Teradata allows subqueries to match on more than one column

• Subqueries may be nested up to 64 levels

SELECT col1 ,col2 ,col3FROM table1WHERE (col1, col3)IN (SELECT col1 ,col2 FROM table2);


Renaming Columns

• Teradata provides several ways to rename or title columns

• (TITLE '') returns the title as a zero length string

SELECT current_date todays_date ,current_date AS todays_date ,current_date (NAMED todays_date) ,current_date AS "Today's Date" ,current_date (TITLE 'Todays''s Date') ,current_date (TITLE '');

todays_date todays_date todays_date Today's Date Todays's Date----------- ----------- ----------- ------------ ------------- 2004/08/14 2004/08/14 2004/08/14 2004/08/14 2004/08/14 2004/08/14


Formatting Numerics

• Teradata provides the ability to format numerics

$ Fixed or floating dollar sign9 Decimal digit (no zero suppress)Z Zero-suppressed decimal digit, Comma—inserted where specified. Decimal point position- Dash character—inserted where specified/ Slash character—inserted where specified% Percent character—inserted where specified

Numeric

formatting

symbols:

SELECT 123 (FORMAT '99999999'), 123 (FORMAT '9(8)') ,000005 (FORMAT 'Z(5)9'), 1234.56 (FORMAT '$$$,$$9.99') ,5 (FORMAT 'Z9%'), 2225551212 (FORMAT '999/999-9999');

123 123 5 1234.56 5 2225551212 -------- -------- ------ ---------- --- ------------ 00000123 00000123 5 $1,234.56 5% 222/555-1212


Formatting Dates

• Teradata provides the ability to format dates

Y Year as YYYY/Y4 (2004) or YY (04)M Month as MMMM/M4 (August), MMM/M3 (Aug) or MM (08)D Day as DDD/D3 (day of the year) or DD (day of the month)E Day of the week as EEEE/E4 (Monday) or EEE/E3 (Mon), Comma—inserted where specified. Decimal point position- Dash character—inserted where specified/ Slash character—inserted where specifiedB Blank position—inserted where specified

Date

formatting

symbols:

SELECT current_date (FORMAT 'YY/MM/DD') ,current_date (FORMAT 'MMMBDD,BYYYY') ,current_date (FORMAT 'M4BDD,BY4') ,current_date (FORMAT 'YYDDD');

Date Date Date Date-------- ------------ ------------------ -----04/08/14 Aug 14, 2004 August 14, 2004 04227


Using FORMAT with SQL Assistant

• Any specified FORMAT must always be applied to a character string

• If the column is not a character data type, the FORMAT will be ignored.

• FORMAT syntax must precede the specified conversion data type syntax.


Attribute Functions

TYPE

TITLE

FORMAT

NAMED

CHARACTERS

There are five specified attribute functions used to determine attributes for columns and expressions:

Query Results

SELECT DISTINCT TYPE (col1)FROM table1;

INTEGER

SELECT DISTINCT TITLE (col1)FROM table1;

col1

SELECT DISTINCT FORMAT (col1)FROM table1;

9(10)

SELECT DISTINCT NAMED (col1)FROM table1;

col1

SELECT DISTINCT CHARACTERS (col2)FROM table1;

10

Examples:


Inner Join Syntax

• Teradata supports the ON Join and WHERE Join Syntax for Inner Joins

SELECT A.col1 ,B.col2FROM table1 A INNER JOIN table2 BON A.col1 = B.col1;-----

SELECT A.col1 ,B.col2FROM table1 A, table2 BWHERE A.col1 = B.col1;


Outer Join Syntax

• Teradata supports the ON Join Syntax for Outer Joins

SELECT A.col1 ,B.col2FROM table1 A LEFT OUTER JOIN table2 BON A.col1 = B.col1WHERE A.col2 = 'value';-----

SELECT A.col1 ,B.col2FROM table1 A RIGHT OUTER JOIN table2 BON A.col1 = B.col1;-----

SELECT A.col1 ,B.col2FROM table1 A FULL OUTER JOIN table2 BON A.col1 = B.col1;


Multi-Table Join Syntax

• Teradata supports the ability to join up to 64 tables (63 join conditions)

SELECT A.col1 ,B.col2 ,C.col3 ,D.col4 ,E.col5FROM table1 A INNER JOIN table2 BON A.col1 = B.col1 LEFT OUTER JOIN table3 CON A.col1 = C.col1 RIGHT OUTER JOIN table4 DON A.col1 = D.col1 FULL OUTER JOIN table5 EON A.col1 = E.col1;


UNION ALL Operator

• Teradata supports the ALL keyword with the UNION Operator to sustain duplicate rows

SELECT col1 FROM table1UNION ALLSELECT col1 FROM table2;


UPDATE Using Subqueries or Joins

UPDATE table1 SET col3 = col3 + 1 WHERE col1 IN (SELECT col1 FROM table2 WHERE col2 LIKE '%update%');

UPDATE table1 SET table1.col3 = table1.col3 + 1 WHERE table1.col1 = table2.col1 AND table2.col2 LIKE '%update%';

Using a Subquery:

Using a Join:

• Updates with joins and subqueries allow a table’s rows to be updated based on information in another table


DELETE Using Subqueries or Joins

DELETE table1 WHERE col1 IN (SELECT col1 FROM table2 WHERE col2 LIKE '%delete%');

DELETE table1 WHERE table1.col1 = table2.col1 AND table2.col2 LIKE '%delete%';

Using a Subquery:

Using a Join:

• Deletes with joins and subqueries allow a table’s rows to be deleted based on information in another table


Upsert - UPDATE ELSE INSERT

• The Upsert operation will attempt to update a single row based on its Primary Index value. If the update fails because the row does not exist the row will be inserted.

Table definition:

CREATE TABLE Table1 ( Col1 INTEGER ,Col2 CHAR(10) ,Col3 SMALLINT) UNIQUE PRIMARY INDEX (Col1);

Upsert example:

UPDATE table1 SET col3 = 123 WHERE col1 = 100 ELSE INSERT INTO table1 VALUES (100,'ABC',123);

The INSERT and UPDATE must reference the same single row of the same table. The UPDATE must use the Primary Index of the table. The target table may be a table or a view.

The INSERT and UPDATE must reference the same single row of the same table. The UPDATE must use the Primary Index of the table. The target table may be a table or a view.


Questions?

Raise your virtual hand to let us know you have a question

Type your question in this box I am not clear about the use of triggers

I am not clear about the use of triggersJohn Q Public

Questions can be submitted at any time. We will answer questions using the text chat window at several scheduled breaks throughout the session.

Then Click Send

Select All Participants from the ‘Send to’ drop down


Macro Definition

• Macros contain one or more prewritten SQL statements.

• Macros are a Teradata extension to ANSI SQL.

• Macros are stored in the Teradata Data Dictionary.

• To execute a macro requires the user to have the EXEC privilege on the macro.

• Explicit privileges on the tables or views used by the macro are not needed by the executing user.

• Macros may contain only one DDL statement - the last or the only statement in the macro.

Macro-related commands:

CREATE MACRO macroname AS( . . . );

Define a macro and storeit in the DD.

EXECute macroname; Execute statements withina macro.

SHOW MACRO macroname; Display a macro.

REPLACE MACRO macroname AS(. . . );

Apply changes to a macroor create a new macro.

DROP MACRO macroname; Remove a macrodefinition from the DD.

EXPLAIN EXEC macroname; Display EXPLAIN text forthe macro's execution.


Macro Examples

Create the macro:

CREATE MACRO macro1 AS ( SELECT col1, col2 FROM table1; );

Execute the macro:

EXEC[UTE] macro1;

Modify the macro:

REPLACE MACRO macro1 AS ( SELECT col1, col2, col3 FROM table1; );

Explain the macro:

EXPLAIN EXEC macro1;

Remove the macro:

DROP MACRO macro1;


Parameterized Macros

• Parameterized macros allow substitutable variables• Values for these variables are supplied at runtime

Create the macro:

CREATE MACRO macro2 (val1 INTEGER, val2 INTEGER) AS ( SELECT * FROM table1 WHERE col1 = :val1 AND col3 = :val2; );

Execute the Macro:

EXEC macro2 (100,200);


SAMPLE Function

• The SAMPLE function allows sampling of data based on the actual number of rows or a percentage of the rows

Sample a number of rows:

SELECT * FROM table1 SAMPLE 10;

Sample a percentage of rows:

SELECT * FROM table1 SAMPLE .25;


SAMPLE Function - SAMPLEID• SAMPLEID assigns an ID value (i.e. 1, 2, 3, 4 …) to a specific sample set

Sample a number of rows:

SELECT sampleid, col1 FROM table1 SAMPLE 10, 20, 30;

Sample a percentage of rows:

SELECT sampleid, col1 FROM table1 SAMPLE .25, .25, .50 ORDER BY 1;

SampleId col1 ----------- --------------- 1 1024 1 1008 2 1004 2 1011 3 1021 3 1017 3 1006 3 1018


NULLIFZERO and ZEROIFNULL

• NULLIFZERO will return NULL if the specified value is zero

SELECT NULLIFZERO(col3) FROM table1;

• ZEROIFNULL will return zero if the specified value is NULL

SELECT ZEROIFNULL(col3) FROM table1;


Views and LOCKING FOR ACCESS

• LOCKING FOR ACCESS will apply a "dirty" read lock on the target table

CREATE VIEW view1 asLOCKING TABLE table1 FOR ACCESSSELECT col1 AS c1 ,col2 AS c2 ,col3 AS c3FROM table1;

SELECT c1, c2 FROM view1ORDER BY c1;


CHARACTER_LENGTH Function

• The CHARACTER_LENGTH function counts the number of characters in the specified string

• The CHARACTER_LENGTH function may also be expressed using non-ANSI compliant variants:

CHARACTERS

CHARS

CHAR

SELECT col1, col2FROM table1WHERE CHARACTER_LENGTH (col2) > 5;

SELECT col1, col2 FROM table1 WHERE CHAR(col2) > 5;


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34781 Cannon

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