Tom Lane kirjutas E, 21.04.2003 kell 09:25:
> Dennis Björklund <db@zigo.dhs.org> writes:
> > The item i'm extra curious about is
> > * Add SQL99 WITH clause to SELECT (Tom, Fernando)
>
> Actually, Andrew Overholt is the guy doing the work on that ...
Any pointers to the work he has done ?
I have done some as well, with the final aim being WITH RECURSIVE
> Fernando and I are, um, supervising.
> > The simple non recursive case can be implemented in a straight forward
> > (but stupid) way, where one "just" substitute in for the variables.
>
> I don't see a lot of interest in the non-recursive case; it seems just
> a bizarre alternate syntax for subselect-in-FROM.
There are useful cases when the tree of subqueries forks, i.e. where 2nd
and 3rd subselects in WITH both use the first.
> The recursive case is interesting and useful though.
Is Andrew Overholt doing the simple case (alternative to the the table
function we already have) or is he trying to solve any/all of the
general cases ?
Is he doing also the <search or cycle clause> and depth/breadth first
variants ?
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Hannu