PostgreSQL – IS NULL

IS NULL condition is used in the WHERE clause to identify records that do not have a value.

Syntax:

SELECT * FROM table_name WHERE column_name IS NULL;

Consider an employee table as shown below:

id	first_name	last_name	department	salary	email
101	bryan	walker	sales	50,000	bryan.walker@email.com
102	alex	carpenter	accounts	55,000	alex.carpenter@email.com
103	sam	white	sales	60,000	sam.white@egmail.com
104	john	barry	sales	54,000	john.barry@email.com
105	bill	wood	accounts	65,000
106	robert	hopkins	support	70,000
107	david	lee	support	72,000	david.lee@email.com
108	jack	sears	support	65,000
109	tom	young	sales	55,000	tom.young@email.com

Below is the SQL query to return employees that did not provide an email address:

SELECT * FROM employee WHERE email IS NULL;

id first_name last_name department salary  email
--- --------- --------- ---------- ------  -------
105 bill       wood      accounts   65000
106 robert     hopkins   support    70000
108 jack       sears     support    65000