Types of SQL Commands

Type of SQL statements are divided into five different categories: 

1. Data definition language (DDL)
2. Data manipulation language (DML), 
3. Data Control Language (DCL), 
4. Transaction Control Statement (TCS), 
5. Session Control Statements (SCS).

DDL:(Create,Alter,Drop,Truncate,Rename)

Statement	Description
CREATE	Create new database/table.
ALTER	Modifies the structure of database/table.
DROP	Deletes a database/table.
TRUNCATE	Remove all table records including allocated table spaces.
RENAME	Rename the database/table.

DML:(Insert,Update,Delete,Merge,Lock Table,Call Explain Plan)

Statement	Description
SELECT	Retrieve data from the table.
INSERT	Insert data into a table.
UPDATE	Updates existing data with new data within a table.
DELETE	Deletes the records rows from the table.
MERGE	MERGE (also called UPSERT) statements to INSERT new records or UPDATE existing records depending on condition matches or not.
LOCK TABLE	LOCK TABLE statement to lock one or more tables in a specified mode. Table access denied to a other users for the duration of your table operation.
CALL EXPLAIN PLAN	Statements are supported in PL/SQL only for executed dynamically. CALL a PL/SQL program or EXPLAIN PATH access the data path.

DCL Command:(Grant,Revoke,Analyze,Audit)

Statement	Description
GRANT	Gives privileges to user for accessing database data.
REVOKE	Take back for given privileges.
ANALYZE	ANALYZE statement to collect statistics information about index, cluster, table.
AUDIT	To track the occurrence of a specific SQL statement or all SQL statements during the user sessions.

TCS:(Commit,Rollback,Savepoint)

Statement	Description
COMMIT	Permanent work save into database.
ROLLBACK	Restore database to original form since the last COMMIT.
SAVEPOINT	Create SAVEPOINT for later use ROLLBACK the new changes.

SCS :(Alter Session,SET Role):

Statement	Description
ALTER SESSION	ALTER SESSION statement to modify conditions or parameters that are affect to your database connection.
SET ROLE	SET ROLE statement to enable or disable the roles that are currently enabled for the session.