NULLIF

Returns a null value if the two specified expressions are equal.

Syntax

NULLIF ( expression , expression )

Arguments

expression

Is any valid scalar expression.

Return types

Returns the same type as the first expression.

NULLIF returns the first expression if the two expressions are not equal. If the expressions are equal, NULLIF returns a null value of the type of the first expression.

Example

SELECT dept
     , NULLIF(current_year, previous_year) AS LastBudget
  FROM budgets;

See Also