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List:       postgis-users
Subject:    [postgis-users] Query re boolean results and efficiency
From:       L Bogert-OBrien <dlawbob () ncf ! ca>
Date:       2010-08-22 19:55:26
Message-ID: 10b27e10f0ec.10f0ec10b27e () ncf ! ca
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In a previous posting, I saw the following suggestion:
> 
> ...you could do something like this:
> select count(*)
>        from 
>           public.table1 as a,
>            public._sample_extent as b
>        where 
>          ST_Intersects(a.geom,b.geom)=true
> 

I was wondering, doesn't 
"WHERE ST_Intersects(a.geom,b.geom)"
have the same output as
"WHERE ST_Intersects(a.geom,b.geom)=true"
and wouldn't it actually be more real time efficient to do the first
one, since you don't have to do the extra check with whether it is equal
to true or not?  Or is the PostgreSQL compiler smart enough to make the
two exactly the same when it comes to efficiency?

Regards,

Loretta
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