>Naomik hi,
>
>Very sorry, but this also does not give the desired result. Have now for the time being decided to go on a completely different road and abonded this aproach - does not seem to be possible.
>
>Thanks for moral support
>
>Koen

Koen,

Did you check my other reply?

You need to start with 1/2 depending on the condition. The index is indeed possible, I'm sorry I wasted time yesterday, but the latest index should have worked.

In other words,
if empty field2 then '1'+ field1 + field2 + field3
if field2 is not empty, then
'2' + field2 + field2 + field3 (some manipulation on it).