CaseExpression.Case abbreviation NULLIF

Returns NULL if the operands are equal otherwise returns the first operand

Format

NULLIF( Operand1, Operand2 )

Remarks

This is a shorthand form of the CASE statement.

The expression:

NULLIF(x,y)

is equivalent to:

CASE WHEN x = y THEN NULL ELSE x END

The return value is either NULL or the first operand.

Both Operand1 and Operand2 can be any expression.