Hi @REGINA LONG
Your original expression seems to be a crystal report expression. I don't know much about Crystal Reports. I don't quite understand the @Null Number in the original expression. Does it return nothing? I wrote the following expression based on my understanding:
=IIf(IsNothing(Fields!ORDER_TIME.Value),nothing,IIf(IsNothing(Fields!RESULT_TIME.Value),nothing,IIf(Fields!ORDER_TIME.Value<=Fields!RESULT_TIME.Value,DateDiff("s",Fields!ORDER_TIME.Value,Fields!RESULT_TIME.Value),nothing)))
Preview:
Best regards,
Aniya