Class 12 SQL Queries CBSE Computer Science | Exam-Ready Guide

Class 12 SQL Queries (CBSE Computer Science) – Complete Exam-Ready Guide

SQL (Structured Query Language) is one of the most scoring sections in CBSE Class 12 Computer Science. Almost every year, 15–20 marks are directly based on SQL queries. The good news is that questions repeat in pattern, and with proper practice, SQL can help you pass easily and score high.

This article explains Class 12 SQL queries in a clear, simple, and exam-oriented way, so students can understand and revise quickly before exams.

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Why SQL Is Important for CBSE Class 12

• Direct step-based marking

• Easy to score with correct syntax

• Frequently repeated query patterns

• Comes in MCQs, short answers, and long answers

If you prepare SQL well, half the paper becomes manageable.

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SQL Syllabus for Class 12 (Quick Overview)

Area	Topics Covered
Database Basics	Table, record, field, keys
DDL Commands	CREATE, ALTER, DROP
DML Commands	INSERT, UPDATE, DELETE
Queries	SELECT with conditions
Functions	COUNT, SUM, AVG, MAX, MIN
Clauses	WHERE, ORDER BY, GROUP BY, HAVING
Operators	AND, OR, BETWEEN, IN, LIKE
Joins	Simple joins (as per syllabus)

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Basic SQL Table Structure (Example)

STUDENT (RollNo, Name, Class, Marks, City)

Understanding the table structure is very important before writing queries.

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Most Important SQL Commands for Class 12

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1. CREATE TABLE

Used to create a new table.

CREATE TABLE Student (
RollNo INT PRIMARY KEY,
Name VARCHAR(20),
Marks INT,
City VARCHAR(20)
);

Always remember data types and brackets.

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2. INSERT INTO

Used to insert records into a table.

INSERT INTO Student VALUES (1, 'Aman', 85, 'Delhi');

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3. SELECT (Most Important)

Used to retrieve data.

Select All Records

SELECT * FROM Student;

Select Specific Columns

SELECT Name, Marks FROM Student;

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4. WHERE Clause

Used to apply conditions.

SELECT * FROM Student WHERE Marks > 80;

WHERE is almost compulsory in board questions.

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5. Operators in SQL (Very Important)

Operator	Use
AND	Multiple conditions
OR	Any one condition
BETWEEN	Range
IN	Multiple values
LIKE	Pattern matching

Example:

SELECT * FROM Student WHERE City = 'Delhi' AND Marks > 70;

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6. ORDER BY

Used to sort data.

SELECT * FROM Student ORDER BY Marks DESC;

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7. Aggregate Functions (Very Scoring)

Function	Use
COUNT()	Number of records
SUM()	Total
AVG()	Average
MAX()	Highest value
MIN()	Lowest value

Example:

SELECT AVG(Marks) FROM Student;

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8. GROUP BY and HAVING

Used with aggregate functions.

SELECT City, COUNT(*) FROM Student GROUP BY City;

SELECT City, COUNT(*) FROM Student 
GROUP BY City 
HAVING COUNT(*) > 2;

HAVING is used instead of WHERE with GROUP BY.

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9. UPDATE Command

UPDATE Student SET Marks = 90 WHERE RollNo = 1;

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10. DELETE Command

DELETE FROM Student WHERE Marks < 40;

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Most Repeated SQL Questions in CBSE Exams

Question Type	Frequency
SELECT with WHERE	Very High
Aggregate functions	High
INSERT command	High
UPDATE / DELETE	Medium
GROUP BY queries	High

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How to Write SQL Answers in Board Exam

✔ Write keywords in capital letters
✔ End queries with semicolon (;)
✔ Avoid spelling mistakes
✔ Follow proper syntax order
✔ Do not write extra explanations

Even a small syntax error can cut marks.

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One-Day SQL Revision Plan

Time	Topic
Morning	SELECT, WHERE, operators
Afternoon	Aggregate functions
Evening	GROUP BY, HAVING
Night	Practice 10 queries

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Common Mistakes to Avoid

Forgetting semicolon
Wrong spelling of commands
Using WHERE with aggregate functions
Mixing column names

Avoid these and SQL becomes easy marks.

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Final Tips for Students

SQL is not about memorising answers. It is about understanding patterns. Practice queries daily, write syntax carefully, and you can score full marks from SQL.

Practice, Revise, Stay calm

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