Hello, I have a SQL query:
SELECT CASE WHEN umowy.numer_umowy IS NULL THEN 0 END AS numer_umowy FROM umowy WHERE umowy.data_podpisania IS NOT NULL AND umowy.id_wnioski IN (SELECT CASE WHEN wnioski.id_wnioski IS NULL THEN 0 END AS id_wnioski FROM wnioski LEFT JOIN kategorie_wnioskow ON kategorie_wnioskow.id_kategorie_wnioskow=wnioski.id_kategorie_wnioskow WHERE kategorie_wnioskow.id_kategorie_wnioskow_typ=1) AND umowy.rok=2014 How do I stop if "NUMER_UMOWY" is NULL is returned to "0" and not null My database is Firebird 2.5
