Re: [HACKERS] what standard say ...

>
> vac=> \d test
>
> Table    = test
> +----------------------------------+----------------------------------+-------+
> |              Field               |              Type                | Length|
> +----------------------------------+----------------------------------+-------+
> | x                                | int4                             |     4 |
> | y                                | int4                             |     4 |
> +----------------------------------+----------------------------------+-------+
> vac=> select count(*) from test where exists (select t1.y from test t1 where t1.y = x);
>                                                                                     ^
> Is this correlated subquery or not ?
> (Note, that I don't use x with t1. prefix here)
> With current parser this works as un-correlated subquery...
> Is this Ok and I have to re-write query as
>
> vac=> select count(*) from test t2 where exists
>                                 ^^
> (select t1.y from test t1 where t1.y = t2.x);
>                                        ^^^
> to get correlated one ?
>
> Vadim
>
>

I am almost sure this is uncorrelated.  If an unqualified varaiable
appears in a subquery, it matches the closest table it can find.

I am not sure about the standard, but logic would suggest this is the
way it should work.

And, of course, that is what the parser does.

--
Bruce Momjian
maillist@candle.pha.pa.us