>First join is incorrect if you have multiple previous records.

just ...

*-- To test a condition
INSERT INTO Agenda (iid , ddate , itraiterId , nstock ) VALUES ( 4 , vp_date -2 , 3 , 6)
INSERT INTO Agenda (iid , ddate , itraiterId , nstock ) VALUES ( 4 , vp_date -3 , 3 , 4)
INSERT INTO Agenda (iid , ddate , itraiterId , nstock ) VALUES ( 4 , vp_date -4 , 3 , 2)


I want the Only the value for vp_date -2 ( = the most recent day of vp_date )

>
>>Naomi,
>>
>>
>>You are right.
>>
>>

>> UPDATE ap ;
>>    SET nstock = pd.nstock ;
>>    FROM Agenda ap;
>>    JOIN (;
>>    SELECT ag.nstock, ag.iid FROM Agenda ag WHERE ag.ddate < (vp_date) ;
>>    UNION ALL ;
>>    SELECT T.nstock, dt1.iid ;
>>    FROM ( ;
>>    SELECT iid,itraiterId ;
>>    FROM Agenda ag2 ;
>>    WHERE ddate = (vp_date) ;
>>    AND NOT EXISTS (SELECT * FROM Agenda ag3 ;
>>    WHERE ag3.ddate < (vp_date) ;
>>    AND ag3.iid  = ag2.iid) ;
>>    ) dt1 ;
>>    JOIN Traiter T ON T.iid = dt1.itraiterId 	;
>>    ) pd ON ap.iid = pd.iid ;
>>    WHERE ap.ddate = vp_date
>>

>>
>>Give a good result
>>
>>bernhart
>>