Re: subqueries - Mailing list pgsql-general

From Tom Lane
Subject Re: subqueries
Date
Msg-id 7183.1119224766@sss.pgh.pa.us
Whole thread Raw
In response to subqueries  (Tomasz Grobelny <tomasz@grobelny.oswiecenia.net>)
List pgsql-general
Tomasz Grobelny <tomasz@grobelny.oswiecenia.net> writes:
> I have such a statement:
> select * from (subquery1) as foo, (subquery2) as bar;
> Both subqueries are reasonably fast (<0.5s) and generate results that have
> several (<10) rows but the whole query takes forever to execute.

The above is an unconstrained join: you are asking for the cross product
of the two subqueries.  It seems unlikely that that is what you really
want.  Perhaps you meant "subquery1 UNION ALL subquery2"?

            regards, tom lane

pgsql-general by date:

Previous
From: "Andres"
Date:
Subject: Insert behavior in transaction
Next
From: "Grant Morgan"
Date:
Subject: unicode and =