Types of SQL Commands

Welcome back to Day 7 of the SQL tutorial series! 👋

Today, let’s explore the 5 main types of SQL commands — this will help you organize your learning and know whyyou’re writing a specific SQL statement.

📌 The 5 Types of SQL Commands

Category	Purpose	Examples
DDL	Data Definition Language	CREATE, ALTER, DROP
DML	Data Manipulation Language	INSERT, UPDATE, DELETE
DQL	Data Query Language	SELECT
DCL	Data Control Language	GRANT, REVOKE
TCL	Transaction Control Language	COMMIT, ROLLBACK, SAVEPOINT

DDL – Data Definition Language

DDL commands define and modify the structure of the database objects like tables, schemas, and indexes.

Command	Description
CREATE	Creates new databases, tables, views, indexes
ALTER	Modifies an existing table (add/remove columns)
DROP	Deletes a table or database
TRUNCATE	Removes all data from a table but keeps the structure

DML – Data Manipulation Language

DML commands are used to modify the data inside tables.

Command	Description
INSERT	Adds new data
UPDATE	Modifies existing data
DELETE	Removes data from a table

DQL – Data Query Language

DQL includes the SELECT statement, used to query data from one or more tables.

Command	Description
SELECT	Retrieves data from a table

DCL – Data Control Language

DCL deals with permissions and access control.

Command	Description
GRANT	Gives user access privileges
REVOKE	Removes user access privileges

TCL – Transaction Control Language

TCL commands manage changes made by DML statements. They ensure data integrity and consistency in transactions.

COMMIT	Saves all changes made in the current transaction
ROLLBACK	Undoes changes since the last COMMIT
SAVEPOINT	Sets a point to rollback to later

🚀 Day 7: Types of SQL commands