How to combine two conditions : Exists and Item not null ?

Question

Hello !
I have a flash chart region that I would like to display only if two conditions are both true.
The first condition is this one :
Exists (SQL query returns at least one row) :
select 1
from    observatoire.fiche aa, observatoire.activite_faite bb
where   aa.fiche_id = bb.fiche_id
and     bb.fiche_id = aa.fiche_id
AND     bb.activites_id = TO_NUMBER(:P23_ACTIVITES_ID)
AND     TRUNC(aa.date_activite, 'YYYY') = TRUNC(TO_DATE(:P23_ANNEE, 'YYYY'), 'YYYY')And the second condition would be :
Item not null :
P23_ACTIVITES_IDHow to combine these two conditions into one display condition ?
Thank you .
Christian

Answer 1

Hello,
The issue is that you're doing -
TO_NUMBER(:P23_ACTIVITES_ID)When you leave the Null return value blank like that, you'll typically see '%null%' used in session state (i.e. it's not actually null). Obviously '%null%' can't be converted to a number, hence the error you're seeing.
A simple solution would be to make your null return value -1 or some other value that is guaranteed not to be a valid id (and alternative is to convert the %null% to a real null via an App/Page process etc (if you search this forum you'll find a few examples on how to do that). Another alternative is to use a DECODE to detect the '%null%' etc.
Hope this helps,
John.
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