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Version: current [25.x]

Categories: Conditional

NULLIF

Compares two expressions. If the values in each expression are equal, returns NULL and, if they are not equal, returns the value of the first expression.

Syntax​

NULLIF(expression1, expression2) → same as input type​

  • expression: The expressions can be any data type, however all the expressions contained in the argument must be of the same type.

Examples

NULLIF example 
SELECT NULLIF(user_id, customer_id)
-- user_id