Re: Odd error in complex query (7.2): Sub-SELECT - Mailing list pgsql-hackers

Philip Warner wrote:
> 
> At 14:36 29/10/01 -0500, Tom Lane wrote:
> >Philip Warner <pjw@rhyme.com.au> writes:
> >> Sorry for the convoluted example:
> >
> >A simplified example is
> 
> And here's a simpler one that seems to avoid views altogether:
> 
>     create table lkp(f1 int);
>     create table t1(f1 int, x int);
> 
>     Select
>          case when Exists(Select * From lkp where lkp.f1 = t1.f1) then
>              'known'
>          else
>              'unknown'
>          end as status,
>          sum(x)
>     from t1
>     group by 1;
> 

A bit off-tppic question, but is our optimiser smart enough to 
recognize the query inside exists as LIMIT 1 query ?

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Hannu