NULLIF: Returning a Null Value When Parameters Are Equal

How to:

NULLIF returns a null (missing) value when its parameters are equal. If they are not equal, it returns the first value. The field to which the value is returned should have MISSING ON.

Syntax: How to Return a Null Value for Equal Parameters 

NULLIF(arg1,arg2)

where:

arg1,arg2

Any type of field, constant, or expression.

Are the input parameters that are tested for equality. They must either both be numeric or both be alphanumeric.

The output data type is the same as the input data types.

Example: Testing for Equal Parameters

The following request uses NULLIF to test the DAMAGED and RETURNS field values for equality.

DEFINE FILE SALES
NULL1/I4 MISSING ON = NULLIF(DAMAGED, RETURNS);
END
TABLE FILE SALES
PRINT DAMAGED RETURNS NULL1
BY STORE_CODE
ON TABLE SET PAGE NOLEAD
ON TABLE SET STYLE *
GRID=OFF,$
END

The output is shown in the following image.