From: Max Lipsky <maxlipsky@gmail.com>
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Message-Id: <6C9B51CF-C8D0-416A-986D-AE1615A01909@gmail.com>
Date: Fri, 3 Jun 2016 00:31:17 +0300
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Hi All!

Why is too much difference in time execution between these two queries:


SELECT rc.id AS id, rc.name
FROM   realisation_category rc
WHERE  EXISTS (
    SELECT * FROM realisation r, post p WHERE (r.realisation_category_id =
=3D rc.id AND r.site_id =3D 1)
    OR (p.realisation_category_id =3D rc.id AND p.site_id =3D 1)
)
[2016-06-03 01:23:12] 35 row(s) retrieved starting from 1 in 14s 591ms (14s=
 612ms total)


SELECT rc.id AS id, rc.name
FROM   realisation_category rc
WHERE  EXISTS (
    SELECT * FROM realisation r WHERE r.realisation_category_id =3D rc.id A=
ND r.site_id =3D 1
) OR EXISTS (
    SELECT * FROM post p WHERE p.realisation_category_id =3D rc.id AND p.si=
te_id =3D 1
)
[2016-06-03 01:25:25] 35 row(s) retrieved starting from 1 in 64ms (86ms tot=
al)

Thanks

--=20
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