sub queries and caching.

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От mlw
Тема sub queries and caching.
Дата
Msg-id 3B59CE9A.A9516E27@mohawksoft.com
обсуждение исходный текст
Список pgsql-hackers
Take these queries:

select * from foo as F, (select * from bar where name = 'bla') as B where
F.name = B.name
union all
select * from foo as F, (select * from bar where name = 'bla') as B where
F.type = B.type

OR 

create temp table B as select * from bar where name = 'bla';
select * from foo as F, B where F.name = B.name
union all
select * from foo as F, B where F.type = B.type;
drop table B;

My question is, which would be more efficient, or is it a wash?
(A note, I will be calling this from an external programming laguage, PHP, so
the first query would be one Postgres pq_exec call, while the second query
would be three separate calls.)


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