>Hi,
>
>that is not the only problem also the 1st part < INDEX ON IIF(empty(Field2, Field1,Field2) TAG myTag> throws an error. I am beginnen to think I am looking for the impossible. Maybe I should add an other field, just to simplify the indexing, this field could be filled with a condition with aid of a scan, only I am still not sure how to do.
>
>Regards,
>
>Koen

In this one you're now missing parens :)

INDEX ON IIF(empty(Field2, Field1,Field2) TAG myTag

should be

INDEX ON IIF(empty(Field2), Field1,Field2) TAG myTag

Are you saying that my expression still not working after you corrected my first typo?