If your application is huge and may contain confidential data, you should nevertheless be able to create a small sample QVW with sample mock up data that shows what you are trying to achieve (as far as I see, you are operating on a single tables with dates, I believe you should be able to create a sample table easily).
There might be different issues you are coping with:
- It's not clear how your data model looks like and in which fields you are selecting and you are using in your expressions (e.g. FILTER_JOUR_ID vs. JOUR_ID)
Maybe your selections is already limiting the record set in a following expression? Then try a set expression to ignore your selection.
- Maybe your expression is not returning an unambiguous value, in general you should consider using aggregation functions in expressions:
Use Aggregation Functions!
Another method to look up the value of another field could be like
= Only({<JOUR_ID = {'$(=Date(vNdebut))'}>} CN1DEBUT)
or
=MinString({<JOUR_ID = {'$(=Date(vNdebut))'}>} CN1DEBUT)
But double check if the field names are correct and the date formats may need to match:
Dates in Set Analysis
