Postgres 14

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Help with an interesting Postgres question: Why isn't an Index Only Scan used on a partition accessed via the parent table?.

create table test (clientid int, subclientid varchar(100));
insert into test values
(44, '1'),
(44, '9'),
(44, 'BASE'),
(44, '2'),
(45, 'BASE'),
(45, '2'),
(46, 'BASE'),
(46, '1');
8 rows affected

select clientid
from (
  select clientid,
    case when subclientid in ('BASE', '1') then 1 else 2 end as score
  from test
) x
group by clientid
having sum(score) = 2;


clientid


46


  select clientid,
    case when subclientid in ('BASE', '1') then 1 else 2 end as score
  from test


clientid
score


44
1

44
2

44
1

44
2

45
1

45
2

46
1

46
1