From: terry@ashtonwoodshomes.com
To: pgsql-sql@postgresql.org
Subject: query optimization question
Date: Mon, 4 Nov 2002 19:19:46 -0500
Message-ID: <000701c28461$0caaa7c0$2766f30a@development.greatgulfhomes.com> (raw)
The query below is slow because both the lots table and the deficiency_table
table have thousands of records. Can anyone tell me how to do the second
subselect (lot_count) by some method of a join instead of a sub - subselect
OR any other method I can use to optimize this query to make it faster?
The objective of the query is: Tell me for each project, the total number
of deficiencies in the project, and the total number of lots with 1 or more
deficiencies in the project.
SELECT project_id, marketing_name,
(SELECT count(lots.lot_id) AS lot_count
FROM deficiency_table AS dt, lots
WHERE dt.lot_id = lots.lot_id
AND lots.division_id = proj.division_id
AND lots.project_id = proj.project_id
) AS def_count,
(SELECT count(lots.lot_id) AS lot_counter
FROM lots
WHERE lots.division_id = proj.division_id
AND lots.project_id = proj.project_id
AND EXISTS (SELECT 1 FROM deficiency_table AS dt WHERE dt.lot_id =
lots.lot_id)
) AS lot_count
FROM projects AS proj
WHERE proj.division_id = '#variables.local_division_id#'
AND NOT EXISTS (SELECT 1 FROM menu_group_projects WHERE menu_code = 'WA'
AND division_id = proj.division_id AND project_id = proj.project_id AND
status = 'I')
ORDER BY proj.project_id
Thanks in advance
Terry Fielder
Network Engineer
Great Gulf Homes / Ashton Woods Homes
terry@greatgulfhomes.com
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To: pgsql-sql@postgresql.org
Cc: terry@ashtonwoodshomes.com
Subject: Re: query optimization question
In-Reply-To: <000701c28461$0caaa7c0$2766f30a@development.greatgulfhomes.com>
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