Teradata SQL

Introduction to Teradata SQL

SQL – It stands for Structured Query Language. This is the language for accessing and manipulating any Relational Database Management Systems. SQL is a non-procedural and set oriented language, meaning it contains no procedural-type statements. 

Teradata SQL is based on ANSI standards. ANSI stands for American National Standards Institute. Teradata SQL is fully certified at the SQL92 Entry level, with some intermediate, some full and some SQL-99 Core features also implemented. To enhance the capabilities of SQL, Teradata has added extensions that are unique to Teradata. 

SQL Commands- There are three categories of SQL Commands: 

Data Definition Language (DDL) 
Data Manipulation Language (DML) 
Data Control Language (DCL)

Categories of SQL Commands

Data Definition Language (DDL) - this is used for creating various database objects like tables, views, macros, users etc.
The following table summarizes the basic DDL Statements : 

TYPE	PURPOSE
CREATE	To define a database object like new table, new macro, trigger, index, stored procedure, view.
DROP	To remove database objects like table, index, macro, stored procedure, view.
ALTER	Modify table, column, trigger or referential constraints or recompile stored procedure
RENAME	Rename a table, view, trigger, stored procedure
SET	Specifies time zones and the collation or character set for a session
COLLECT STATISTICS	Collect Stats on column/columns or index

Data Manipulation Language (DML) - This is used for the manipulation of data like inserting the records, deleting the records, updating the records etc.

TYPE	PURPOSE
INSERT	Inserting data into a table
UPDATE	Modifies data in one or more rows in a table
Delete	Removing data from table
Comment	Insert a text comment for a table
Checkpoint	CHECKPOINT is a function that writes records to a restart log table that you can use to restart in case of a hardware or software system failure.
Database	Indicates a default database
Merge	Combines both UPDATE and INSERT in a single SQL statement.

Data Control Language(DCL):

database objects or controlling ownership of those objects by using DCL  commands.

SQL statement	Function
GRANT	To give user privileges.
REVOKE	To remove user privileges.
GIVE	To transfer database ownership.