SQL Logical Operators

SQL Logical Operators

SQL Logical Operators are used to combine multiple conditions in SQL queries. These operators help filter results by applying logical conditions to records in a database. Logical operators are mainly used in the WHERE clause to refine search criteria.

In this tutorial, we will cover the different SQL logical operators, their syntax, and practical examples.

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List of SQL Logical Operators

Operator	Description	Example
AND	Returns true if both conditions are true	SELECT * FROM students WHERE age > 18 AND grade = 'A';
OR	Returns true if at least one condition is true	SELECT * FROM students WHERE age > 18 OR grade = 'A';
NOT	Reverses the result of a condition	SELECT * FROM students WHERE NOT grade = 'A';
IN	Checks if a value matches any value in a list	SELECT * FROM students WHERE grade IN ('A', 'B');
BETWEEN	Checks if a value is within a range	SELECT * FROM students WHERE age BETWEEN 18 AND 22;
LIKE	Performs pattern matching	SELECT * FROM students WHERE name LIKE 'A%';
IS NULL	Checks if a value is NULL	SELECT * FROM students WHERE grade IS NULL;

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Syntax of SQL Logical Operators

The general syntax for using logical operators in SQL queries is:

SELECT column_name(s)
FROM table_name
WHERE condition1 LOGICAL_OPERATOR condition2;

For example, to select students who are older than 18 and have a grade of ‘A’:

SELECT * FROM students 
WHERE age > 18 AND grade = 'A';

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Step-by-Step Examples Using SQL Logical Operators

1 Using AND Operator

We will create a students table and insert sample data for demonstration.

CREATE TABLE students (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(50),
    age INT,
    grade CHAR(1)
);

INSERT INTO students (name, age, grade)
VALUES 
('Arjun', 20, 'A'),
('Ram', 18, 'B'),
('Priya', 22, 'A'),
('Neha', 19, 'C'),
('Sita', 21, 'B');

Retrieve students who are older than 18 and have a grade of ‘A’:

SELECT * FROM students
WHERE age > 18 AND grade = 'A';

Result: Returns ‘Priya’ because she is older than 18 and has grade ‘A’.

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2 Using OR Operator

Retrieve students who are older than 18 or have grade ‘A’:

SELECT * FROM students
WHERE age > 18 OR grade = 'A';

Result: Returns ‘Arjun’, ‘Priya’, and ‘Sita’ because at least one condition is true.

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3 Using NOT Operator

Retrieve students who do not have grade ‘A’:

SELECT * FROM students
WHERE NOT grade = 'A';

Result: Returns ‘Ram’, ‘Neha’, and ‘Sita’.

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4 Using IN Operator

Retrieve students whose grade is either ‘A’ or ‘B’:

SELECT * FROM students
WHERE grade IN ('A', 'B');

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5 Using BETWEEN Operator

Retrieve students aged between 18 and 21:

SELECT * FROM students
WHERE age BETWEEN 18 AND 21;

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Conclusion

SQL Logical Operators allow us to combine conditions and refine queries effectively. We explored:

• AND, OR, and NOT for logical condition combinations.
• IN for matching values within a list.
• BETWEEN for range-based filtering.