SQL

DDL (Data Definition Language) - Define database structure

Command	Purpose
CREATE	Create databases, tables, indexes
ALTER	Modify existing database objects
DROP	Delete tables or databases
TRUNCATE	Remove all records from a table
RENAME	Rename database objects

DML (Data Manipulation Language) - Manage data within tables

Command	Purpose
SELECT	Retrieve data from database
INSERT	Add new records
UPDATE	Modify existing records
DELETE	Remove records

DCL (Data Control Language) - Manage permissions

Command	Purpose
GRANT	Give user privileges
REVOKE	Take away user privileges

TCL (Transaction Control Language) - Manage transactions

Command	Purpose
COMMIT	Save transaction changes
ROLLBACK	Undo transaction changes
SAVEPOINT	Set a rollback point

Key Clauses Used with SELECT

• WHERE - Filter results
• ORDER BY - Sort results
• GROUP BY - Group rows
• HAVING - Filter groups
• JOIN - Combine tables
• DISTINCT - Remove duplicates
• LIMIT - Restrict rows returned

Database