Hi
I would actually do it like this…so that the set on the left of JOIN becomes
smaller
SELECT a.item_id, a.create_dt
FROM
( SELECT
item_id, create_dt
FROM
A
WHERE
item_id = 'I001'
AND
category_name = 'C001'
) a
JOIN
b
ON
a.item_id = b.item_id
;
From: Naga Vijay <[email protected]<mailto:[email protected]>>
Reply-To: "[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>
Date: Wednesday, June 12, 2013 9:17 PM
To: "[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>
Subject: Enhancing Query Join to speed up Query
Hi,
Which of the two query options is better?
SELECT a.item_id, a.create_dt
FROM a JOIN b
ON (a.item_id = b.item_id)
WHERE a.item_id = 'I001'
AND a.category_name = 'C001';
- or -
SELECT a.item_id, a.create_dt
FROM a JOIN b
ON (a.item_id = b.item_id AND a.item_id = 'I001')
WHERE a.category_name = 'C001';
Thanks
Naga
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