Hi, I back with this question. Is this really correct because after discussion with team i have now doubt.
We have here parenthesis. Any expression in parenthesis should be first calculated Then this is not test NOT NULL - > NULL only Not ( NULL -> NULL) Regards, Karol Bieniaszewski ----- Reply message ----- Od: "Ivan Přenosil" <[email protected]> Do: <[email protected]> Temat: [firebird-support] Bug? Data: pon., maj 5, 2014 13:44 > this query return 0 > > SELECT count(*) FROM RDB$DATABASE WHERE ((CAST(NULL AS INTEGER) IS NULL AND > CAST(123 AS INTEGER) IS NULL) OR > (CAST(NULL AS INTEGER)=1)) > > when i add "NOT" this query return also 0 > > SELECT count(*) FROM RDB$DATABASE WHERE NOT ((CAST(NULL AS INTEGER) IS NULL > AND CAST(123 AS INTEGER) IS NULL) OR > (CAST(NULL AS INTEGER)=1)) > > > is this a bug? No. Where clause of the first select is True and False or Null -> Null So the second select is Not Null -> Null Ivan
