Jim Buttafuoco wrote:
Jan,
I write queries like this
CREATE VIEW parent_childs AS
SELECT
c.parent,
count(c.state) as childtotal,
sum(case when c.state = 1 then 1 else 0 end) as childstate1,
sum(case when c.state = 2 then 1 else 0 end) as childstate2,
sum(case when c.state = 3 then 1 else 0 end) as childstate3
FROM child c
GROUP BY parent;
It would help if booleans could be casted to integer 1/0 :-) But
performance wise it should be about the same? I think I'll
run some tests later today with real data.
Would an index on NULLIF(state,1) help count(NULLIF(state,1)) ?
Can one build an index on (case when c.state = 3 then 1 else 0 end)?
Thanks,
Jan
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