SQL Operators (CBSE Class 12 Computer Science - 083)

SQL operators are special symbols or keywords used to perform calculations, compare values, and combine multiple conditions in SQL queries. Operators are commonly used with the SELECT, UPDATE, and DELETE statements to filter or manipulate data.

Learning Objectives

• Understand SQL Operators.
• Learn Mathematical Operators.
• Learn Relational Operators.
• Learn Logical Operators.
• Use operators in SQL queries.

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Sample Student Table

The following table will be used throughout this chapter.

StudentID	Name	Gender	Class	Section	City	Marks	DeptID
101	Riya	F	XII	A	Jaipur	95	1
102	Aman	M	XII	B	Delhi	91	2
103	Priya	F	XII	A	Jaipur	88	1
104	Rahul	M	XII	C	Mumbai	76	3
105	Neha	F	XII	B	Delhi	84	2
106	Arjun	M	XII	A	Jaipur	92	1
107	Simran	F	XII	C	Mumbai	81	3
108	Karan	M	XII	B	Delhi	69	2

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SQL Operators

SQL operators are classified into three major categories in the CBSE syllabus:

1. Mathematical Operators
2. Relational Operators
3. Logical Operators

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1. Mathematical Operators

Mathematical operators perform arithmetic calculations on numeric values.

Operator	Description	Example
+	Addition	Marks + 5
-	Subtraction	Marks - 5
*	Multiplication	Marks * 2
/	Division	Marks / 2
%	Modulus (Remainder)	Marks % 2

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Example 1 : Addition

SELECT Name,
Marks,
Marks + 5 AS NewMarks
FROM Student;

Output

Name	Marks	NewMarks
Riya	95	100
Aman	91	96
Priya	88	93

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Example 2 : Multiplication

SELECT Name,
Marks,
Marks*2 AS DoubleMarks
FROM Student;

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Example 3 : Division

SELECT Name,
Marks,
Marks/2 AS HalfMarks
FROM Student;

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2. Relational Operators

Relational operators compare two values and return either TRUE or FALSE.

Operator	Description
=	Equal To
>	Greater Than
<	Less Than
>=	Greater Than or Equal To
<=	Less Than or Equal To
<> or !=	Not Equal To

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Example 1 : Equal To (=)

SELECT *
FROM Student
WHERE City='Jaipur';

Output

StudentID	Name	City
101	Riya	Jaipur
103	Priya	Jaipur
106	Arjun	Jaipur

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Example 2 : Greater Than (>)

SELECT Name,Marks
FROM Student
WHERE Marks>90;

Output

Name	Marks
Riya	95
Aman	91
Arjun	92

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Example 3 : Less Than (<)

SELECT *
FROM Student
WHERE Marks<80;

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Example 4 : Greater Than or Equal To

SELECT *
FROM Student
WHERE Marks>=90;

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Example 5 : Less Than or Equal To

SELECT *
FROM Student
WHERE Marks<=80;

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Example 6 : Not Equal To

SELECT *
FROM Student
WHERE City<>'Delhi';

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3. Logical Operators

Logical operators combine multiple conditions in SQL queries.

Operator	Description
AND	Both conditions must be TRUE.
OR	At least one condition must be TRUE.
NOT	Reverses the condition.

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AND Operator

Returns records only when both conditions are TRUE.

SELECT *
FROM Student
WHERE City='Jaipur'
AND Marks>90;

Output

Name	City	Marks
Riya	Jaipur	95
Arjun	Jaipur	92

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OR Operator

Returns records when either condition is TRUE.

SELECT *
FROM Student
WHERE City='Delhi'
OR Marks>90;

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NOT Operator

Returns records that do not satisfy the given condition.

SELECT *
FROM Student
WHERE NOT City='Delhi';

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Combining Relational and Logical Operators

SELECT *
FROM Student
WHERE Marks>=80
AND Marks<=90;

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Operator Precedence

When multiple operators are used in the same query, SQL evaluates them according to precedence.

Priority	Operator
1	Mathematical Operators
2	Relational Operators
3	NOT
4	AND
5	OR

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Comparison of SQL Operators

Operator Type	Purpose
Mathematical	Performs arithmetic calculations.
Relational	Compares values.
Logical	Combines multiple conditions.

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Common Errors

• Using = instead of == (SQL uses only =).
• Forgetting quotation marks around text values.
• Using AND when OR is required.
• Incorrect use of NOT with conditions.
• Ignoring operator precedence.

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Exam Tips

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Frequently Asked Questions (FAQs)

1. What are SQL operators?

SQL operators are symbols or keywords used to perform calculations, compare values, and combine conditions in SQL statements.

2. Which SQL operators are included in the CBSE syllabus?

Mathematical, Relational, and Logical operators.

3. What is the difference between relational and logical operators?

Relational operators compare values, whereas logical operators combine or modify multiple conditions.

4. Which logical operator returns records only when both conditions are true?

The AND operator.

5. Which operator is used to compare two values for equality?

The = (Equal To) operator.

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Summary

• SQL operators are used to perform calculations and comparisons.
• Mathematical operators perform arithmetic operations.
• Relational operators compare values.
• Logical operators combine multiple conditions.
• Operators are widely used with the SELECT, UPDATE, and DELETE statements.
• Understanding operators is essential for writing SQL queries effectively.