LESS THAN Operator (<) - SQL

Overview

The Less than operator (<) is used to compare two expressions. It returns true if the left expression is less than the right expression. It can be used in SQL queries to filter records based on a comparison.

Syntax:

SELECT number1 < number2

number1 < number2 checks if the value number1 is less than number2.

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 values (TRUE) value

In this example, the Less than operator is used to evaluate whether the 5 < 10 is true. Since 5 is less than 10, the query will return an output of 1, indicating that it is true.

Example:

SELECT 5 < 10

Example: Hard-coded values (FALSE) value

In this example, the Less than operator is used to evaluate whether the 5 < 2 is true. Since 5 is not less than 2, the query will return an output of 0, indicating that it is false.

Example:

SELECT 5 < 2

Example: Query without the WHERE Statement

In this example, we are returning the vacation_days column and a column that checks if each value in the vacation_days column is less than 2. The final output is the original vacation_days column alongside the column checking whether it’s less than 2.

Example:

SELECT vacation_days, vacation_days < 2
FROM company.employees

Example: Query with the WHERE Statement

In this example, we are filtering for rows in the department_id column using the less than operator, we only want department_id less than 3. We are also returning the vacation_days column and a column that checks if each value in the vacation_days column is less than 2. The final output is the original vacation_days column alongside the column checking whether it’s less than 2.

Example:

SELECT vacation_days, vacation_days < 2
FROM company.employees
WHERE department_id < 3