IS NULL Operator - SQL

Overview

The IS NULL Operator in SQL is used to filter the result set to include only the rows where the specified column contains a NULL value. It checks for the presence of NULL values in a column.

Syntax:

SELECT column
FROM table_name
WHERE column1 IS NULL

column1 IS NULL checks if the value in column1 is NULL.

Sample Data:

    
            department_id
            first_name
        
            3
            Frank
        
            2
            Jane
        
            3
            Ashley
        
            NULL
            Glenn
        
            2
            Kelly
        
            1
            Richard
        
            1
            George
        
            5
            Kyle
        
            2
            James
        
            1
            Gustavo

department_id	first_name
3	Frank
2	Jane
3	Ashley
NULL	Glenn
2	Kelly
1	Richard
1	George
5	Kyle
2	James
1	Gustavo

Example

In this example, we are returning the department_id and the first_name column. We then use the IS NULL operator to filter the results to only include rows where the department_id column is null.

Example:

SELECT department_id, first_name
FROM company.employees
WHERE department_id IS NULL