| From: | Atri Sharma <atri(dot)jiit(at)gmail(dot)com> |
|---|---|
| To: | Hannu Krosing <hannu(at)2ndquadrant(dot)com> |
| Cc: | Antonin Houska <antonin(dot)houska(at)gmail(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Removing Inner Joins |
| Date: | 2013-07-10 08:32:24 |
| Message-ID: | CAOeZVifdRMhw10wam9bTp83qJ-=UmX3RqmqogRJ-6TUTGvmr9g@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Wed, Jul 10, 2013 at 1:11 PM, Hannu Krosing <hannu(at)2ndquadrant(dot)com> wrote:
> On 07/10/2013 09:18 AM, Atri Sharma wrote:
>>> Can you please post an example of such a join removal? I mean a query before
>>> and after the removal. Thanks,
>> Courtesy Robert Haas:
>>
>> SELECT foo.x, foo.y, foo.z FROM foo WHERE foo.x = bar.x
>>
>> Conditions:
>>
>> 1) foo.x is not null.
> I guess that this is also not needed. you can just remove rows where
>
> foo.x is null
>
> That is, replace the join with "foo.x is not null"
Yeah, sounds good. We should explore it further.
Regards,
Atri
--
Regards,
Atri
l'apprenant
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