Re: AW: Three types of functions, ala function redux.

Zeugswetter Andreas SB wrote:
>
> > select * from table where col = function() ;
>
> > (2) "function()" returns a number of values that are independent of the
> > query. Postgres should be able to optimize this to be: "select * from
> > table where col in (val1, val2, val3, ..valn)." I guess Postgres can
> > loop until done, using the isDone flag?
>
> I think the above needs a different sql statement to begin with.
> The "= function()" clearly states that function is only allowed to return one row.
>
> The following syntax currently works, and is imho sufficient:
> select * from table where col in (select function());

Both syntaxes work, but always force a table scan. If you have an index
on 'col' it will not be used. If your table has millions of records,
this takes time.

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