IS NULL condition checks NULL values in the table. IS NULL condition is used to fetch matching rows or columns which contain NULL values in the specified condition. IS NULL condition is used in SELECT, UPDATE, DELETE statements.

SELECT column1, column2, …, columnN
 FROM table_name
 WHERE column_name IS NULL; 

UPDATE table_name
SET column1 = value1, column2 = value2, …, columnN = valueN
WHERE column_name IS NULL; 

DELETE FROM table_name 
WHERE column_name IS NULL; 

• column1, column2, …, columnN - Specifies the column names from table.
• table_name – Specifies the name of the table.
• column_name - Specifies the column that used to check for NULL values.

Let us consider below table(s) as an example table(s) to frame the SQL query for getting the desired results.

Scenario – Fetch rows or values having NULL.

Requirement – Fetch all details of employees whose manager_id is NULL. The query was as follows –

SELECT * FROM employee_details WHERE manager_id IS NULL; 

By executing above query, we can get results as shown below –

Scenario – Update the rows that are having NULL values.

Requirement – Update the manager as "Employee0" whose manager is having NULL and having employee id is 001. The query was as follows –

UPDATE employee_details
SET manager_id = "Employee0" 
WHERE manager_id IS NULL AND emp_id = 001; 

By executing above query, we can update the NULL value with "Employee0" in employee_details table whose emp_id is 001. The table after updation was as follows-

Scenario – Delete rows which contain NULL value.

Requirement – Delete employees whose manager is empty. The query was as follows –

DELETE FROM employee_details WHERE manager_id IS NULL; 

By executing above query, we can delete rows which contain null values. The updated table was as follows –