IF Function - SQL

Overview

The IF function in SQL evaluates a condition and returns one value if the condition is true and another value if the condition is false. It is used for conditional logic within queries.

Example:

SELECT IF(vacation_days > 0, 'Some vacation left', 'No vacation left')

Syntax:

SELECT IF(condition, true_result, false_result)

condition is the logical expression to evaluate.

true_result is the value returned if the condition is true.

false_result is the value returned if the condition is false.

Sample Data:

    
            first_name
            vacation_days
        
            Frank
            5
        
            Jane
            2
        
            Ashley
            3
        
            Glenn
            -3
        
            Kelly
            2
        
            Richard
            -7
        
            George
            2
        
            Kyle
            1
        
            James
            -2
        
            Gustavo
            -10

first_name	vacation_days
Frank	5
Jane	2
Ashley	3
Glenn	-3
Kelly	2
Richard	-7
George	2
Kyle	1
James	-2
Gustavo	-10

Example: Hard-coded value

In this example, we are checking to see if 10 is greater than 5 using the IF function. Since the condition is true, it returns the value ‘This is true’.

Example: Query without the WHERE Statement

In this example, we are returning the vacation_days column for each employee and use the IF function to check if the vacation_days are greater than 0. If the condition is true, it returns ‘Some vacation left’ and if it is false, it returns ‘No vacation’.

Example: Query with the WHERE Statement

In this example, we are returning the vacation_days column for each employee with the department_id of 1 and use the IF function to check if the vacation_days are greater than 0. If the condition is true, it returns ‘Some vacation left’ and if it is false, it returns ‘No vacation’.