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How to remove duplicate subqueries - Mailing list pgsql-general

From Andrus
Subject How to remove duplicate subqueries
Date
Msg-id gaqe5n$1nul$1@news.hub.org
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List pgsql-general
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I have query

SELECT ...
(
SELECT ... FROM (q1) p1 WHERE ...
UNION ALL
SELECT ... FROM (q1) p2 WHERE ...
) p3
GROUP BY f1,f2,f3

This query contains q1 query twice.
q1 takes long time to execute. PostgreSQL probably will execute it two
times.

How to force PostgreSQL 8.1 to execute q1 only once ?

Andrus.

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