SQL Commands Explained: Fast Revision Notes for IBPS SO IT Officer

SQL (Structured Query Language) is the standard language used to interact with relational databases. Almost every competitive exam covering DBMS asks questions on SQL command categories, their purpose, and common differences.

This article provides a quick revision of all five SQL command categories with syntax, examples, and exam-focused tips.

Why Should You Learn SQL Commands?

SQL commands allow you to:

• Create databases and tables
• Insert and modify records
• Retrieve information
• Manage transactions
• Control user permissions

Questions on SQL command categories are among the easiest marks in the IBPS SO Professional Knowledge section.

SQL Commands at a Glance

1. DDL (Data Definition Language)

DDL commands define or modify the structure of database objects.

Common Commands

Example

CREATE TABLE Student (
    StudentID INT PRIMARY KEY,
    Name VARCHAR(50)
);

Important Points

• Changes the database structure.
• Usually performs an implicit COMMIT.
• Cannot usually be rolled back.

2. DML (Data Manipulation Language)

DML commands manipulate the records stored inside tables.

Common Commands

Example

INSERT INTO Student
VALUES (101, 'Rahul');

UPDATE Student
SET Name = 'Aman'
WHERE StudentID = 101;

DELETE FROM Student
WHERE StudentID = 101;

3. DQL (Data Query Language)

DQL retrieves data from one or more tables.

Main Command

Example

SELECT Name, Department
FROM Student
WHERE Department = 'IT';

Frequently used clauses include:

• WHERE
• ORDER BY
• GROUP BY
• HAVING
• DISTINCT
• LIMIT

4. DCL (Data Control Language)

DCL controls database access and permissions.

Commands

Example

GRANT SELECT
ON Student
TO user1;

5. TCL (Transaction Control Language)

TCL manages database transactions.

Commands

Example

UPDATE Account
SET Balance = Balance - 1000
WHERE AccountID = 101;

ROLLBACK;

SQL Command Classification Cheat Sheet

DELETE vs TRUNCATE vs DROP

Memory Trick

Remember the order:

DDL → DML → DQL → DCL → TCL

A simple mnemonic is:

"Define → Modify → Query → Control → Transaction"

Exam Tips

• Know the classification of every SQL command.
• Remember that SELECT belongs to DQL.
• Learn the difference between DELETE, TRUNCATE, and DROP.
• Revise transaction commands before studying ACID properties.

Related Topics

• SQL Constraints
• SQL Keys
• SQL Joins
• Aggregate Functions
• Transactions
• ACID Properties

Take this free mock test to test your understanding of the SQL commands and get mastery over them.