Re: problem in select
От | Martijn van Oosterhout |
---|---|
Тема | Re: problem in select |
Дата | |
Msg-id | 20020916173621.B15848@svana.org обсуждение исходный текст |
Ответ на | Re: problem in select ("frank_lupo" <frank_lupo@email.it>) |
Список | pgsql-general |
Well, here's your problem. Using both IN (which is slow) and DISTINCT (which is completely unnessesary). How does this differ from: select titolo,id,anno from ircalend where anno=2002 and exists (select 1 from ircalend_3 where idcalen=ircalend.id) order by anno,titolo; On Mon, Sep 16, 2002 at 08:46:27AM +0200, frank_lupo wrote: > gedis30=# explain select titolo,id,anno from ircalend where anno=2002 and id in(select distinct(idcalend) from ircalend_3)order by anno,titolo; > NOTICE: QUERY PLAN: > Sort (cost=47353.16..47353.16 rows=1 width=49) > -> Seq Scan on ircalend (cost=0.00..47353.15 rows=1 width=49) > SubPlan > -> Materialize (cost=6764.58..6764.58 rows=7111 width=4) > -> Unique (cost=0.00..6764.58 rows=7111 width=4) > -> Index Scan using ircalend_3_idcalend on ircalend_3 (cost=0.00..6586.80 rows=71112 width=4) -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > There are 10 kinds of people in the world, those that can do binary > arithmetic and those that can't.
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