Question : ORDER BY items must appear in the select list if the statement contains a UNION operator.

i have done unions where i did not have to do any order bys.

But when I did a union of 2 select statements, I get the above error; why is this?

thanks

Answer : ORDER BY items must appear in the select list if the statement contains a UNION operator.

You can do it like this:
=iif(Fields!CustomerState.Value = "NY", "Tri-State", iif(Fields!CustomerState.Value = "CT", "Tri-State",iif(Fields!CustomerState.Value = "NJ", "Tri-State", Fields!CustomerState.Value )))