SQL commands are categorized into five primary sub-languages based on their functional role within a database: DDL (structure), DML (data), DQL (data querying), DCL (permissions), and TCL (transactions).

SQL Command Categories Summary

Category [1, 2, 3, 4, 5]	Full Form	Primary Purpose	Common Commands
DDL	Data Definition Language	Defines and alters database structures/schema.	`CREATE`, `ALTER`, `DROP`, `TRUNCATE`
DML	Data Manipulation Language	Adds, modifies, or deletes records within tables.	`INSERT`, `UPDATE`, `DELETE`
DQL	Data Query Language	Retrieves information from the database.	`SELECT`
DCL	Data Control Language	Manages user access, security, and permissions.	`GRANT`, `REVOKE`
TCL	Transaction Control Language	Manages the execution and finality of transactions.	`COMMIT`, `ROLLBACK`, `SAVEPOINT`

Detailed Breakdown & Examples

1. DDL (Data Definition Language)

DDL commands build and change the blueprint of your database. These commands affect tables, views, and indexes. They are auto-committed, meaning the structural changes save instantly and permanently.

CREATE: Generates a brand new table or database.
ALTER: Modifies the layout of an existing table, like adding a new column.
DROP: Erases an entire table or database permanently along with all its data.
TRUNCATE: Wipes all data rows out of a table instantly but keeps the structure intact.

2. DML (Data Manipulation Language)

DML commands are used to modify the actual row-level data stored inside your tables. Unlike DDL, these changes can be reverted before they are permanently saved.

INSERT: Adds new rows of data into a table.
UPDATE: Modifies existing values inside specific rows.
DELETE: Removes specific rows based on a given condition.

3. DQL (Data Query Language)

DQL consists strictly of commands used to read and fetch data. It does not modify anything in the database.

SELECT: Retrieves rows of data from one or multiple tables based on filters.

4. DCL (Data Control Language)

DCL commands handle security, data visibility, and database access privileges for different system users.

GRANT: Gives specific permissions (like reading or writing data) to a user account.
REVOKE: Cancels or takes back previously assigned privileges.

5. TCL (Transaction Control Language)

TCL commands manage groups of DML commands to ensure they run safely as a single unit of work (a transaction). They protect data integrity by preventing partial data updates.

COMMIT: Saves all active transactional data changes permanently to the disk.
ROLLBACK: Erases temporary changes made during the current transaction if an error occurs.
SAVEPOINT: Places a temporary marker inside a transaction so you can roll back to it later without losing everything.

Types of Sql Commands

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