Submitted by: @pavel-zotov

(created as separate ticket after Adriano suggestion; text below was moved here from CORE5153)

Consider following sample:

set list on;
set count on;
select 1 as check_ok
from rdb$database r
group by r.rdb$relation_id
having count(*) not in (select -1 from rdb$database r2)
;

NOT-IN subquery has not NULLs so HAVING clause should NOT prevent from returning one row.

But results differ on 2.5 vs (3.0 RC2 and 4.0 Unstable):

C:\MIX\firebird\QA\fbt-repo\tmp>C:\MIX\firebird\fb25\bin\isql /:e25 -z -i c5153x.sql
ISQL Version: WI-V2.5.6.26980 Firebird 2.5
Server version:
WI-V2.5.6.26980 Firebird 2.5
WI-V2.5.6.26980 Firebird 2.5/tcp (csprog)/P12
WI-V2.5.6.26980 Firebird 2.5/tcp (csprog)/P12

CHECK_OK 1

Records affected: 1

C:\MIX\firebird\QA\fbt-repo\tmp>C:\MIX\firebird\fb30\isql /:e30 -z -i c5153x.sql
ISQL Version: WI-V3.0.0.32383 Firebird 3.0 Release Candidate 2
Server version:
WI-V3.0.0.32383 Firebird 3.0 Release Candidate 2
WI-V3.0.0.32383 Firebird 3.0 Release Candidate 2/tcp (csprog)/P13
WI-V3.0.0.32383 Firebird 3.0 Release Candidate 2/tcp (csprog)/P13
Records affected: 0

C:\MIX\firebird\QA\fbt-repo\tmp>C:\MIX\firebird\fb40\isql /:e40 -z -i c5153x.sql
ISQL Version: WI-T4.0.0.32400 Firebird 4.0 Unstable
Server version:
WI-T4.0.0.32400 Firebird 4.0 Unstable
WI-T4.0.0.32400 Firebird 4.0 Unstable/tcp (csprog)/P13
WI-T4.0.0.32400 Firebird 4.0 Unstable/tcp (csprog)/P13
Records affected: 0

PS. Versions: WI-V3.0.0.32383 and WI-T4.0.0.32400 - were downloaded from snapshot directory just now:

C:\1TMP>dir /-c Firebird-3.0.0.32383-0_Win32.7z Firebird-4.0.0.32400-0_Win32.7z |findstr /i fir
23.03.2016 16:48 6562751 Firebird-3.0.0.32383-0_Win32.7z
23.03.2016 16:46 5401474 Firebird-4.0.0.32400-0_Win32.7z

Unfortunately, we have no more (or not yet ?) subsequent number of builds after moving on git, so they are the same as before.

Commits: 83e9537 f72de29