• Data Definition Language (DDL) – to define and modify the structure of a database.
• Data Manipulation Language (DML) – to access, manipulate, and modify data in a database.
• Data Control Language (DCL) – to control user access to the data in the database and give or revoke privileges to a specific user or a group of users.
• Transaction Control Language (TCL) – to control transactions in a database.
• Data Query Language (DQL) – to perform queries on the data in a database to retrieve the necessary information from it.

• DDL: CREATE, ALTER TABLE, DROP, TRUNCATE, and ADD COLUMN
• DML: UPDATE, DELETE, and INSERT
• DCL: GRANT and REVOKE
• TCL: COMMIT, SET TRANSACTION, ROLLBACK, and SAVEPOINT
• DQL: – SELECT

                +---------------------+
                |   SQL Commands      |
                +----------+----------+
                           |
                           v
                +----------+----------+
                |     DDL (Data      |
                | Definition Language)|
                +----------+----------+
                           |
                 +---------+---------+
                 |                   |
            +----+----+        +-----+-----+
            | CREATE  |        |  ALTER   |
            | TABLE   |        |  TABLE   |
            +----+----+        +-----+-----+
                 |                   |
                 v                   v
        +--------+---------+   +-----+-------+
        |                  |   |             |
 +------|   DROP TABLE     |   |  MODIFY     |
 |      |                  |   |  TABLE      |
 |      +------------------+   +-------------+
 |                                        |
 |                                        v
 |                               +--------+--------+
 |                               |                  |
 +-------------------------------|  RENAME TABLE    |
                                 |                  |
                                 +------------------+

                +----------+----------+
                |    DML (Data       |
                | Manipulation Language)|
                +----------+----------+
                           |
                 +---------+---------+
                 |                   |
            +----+----+        +-----+-----+
            | INSERT  |        |  UPDATE   |
            | INTO    |        |  TABLE    |
            +----+----+        +-----+-----+
                 |                   |
                 v                   v
        +--------+---------+   +-----+-------+
        |                  |   |             |
 +------|   DELETE FROM    |   |  MERGE INTO  |
 |      |                  |   |    TABLE    |
 |      +------------------+   +-------------+
 |                                        |
 |                                        v
 |                               +--------+--------+
 |                               |                  |
 +-------------------------------|  TRUNCATE TABLE  |
                                 |                  |
                                 +------------------+

                +----------+----------+
                |    DCL (Data       |
                | Control Language)   |
                +----------+----------+
                           |
                 +---------+---------+
                 |                   |
            +----+----+        +-----+-----+
            | GRANT  |        |  REVOKE   |
            |        |        |  PRIVILEGES|
            +----+----+        +-----+-----+
                                       |
                                       v
                              +--------+--------+
                              |                  |
                              |  SET TRANSACTION|
                              |                  |
                              +------------------+