What is IS NULL and IS NOT NULL?

Parthiban Kannan

Updated on January 8, 2026

< 1 min read

IS NULL is used to check if a column contains a NULL value.
IS NOT NULL checks that a column has a non-NULL value.
They are used in WHERE clauses to filter data with missing or existing values.
In my project, IS NULL identified customers without email addresses.
IS NOT NULL was used to select only valid transactions for reporting.
These operators ensure correct handling of incomplete data.
They are essential for accurate queries and data validation.