Re: broken join optimization? (8.0)

chester c young wrote:
> in php (for example) it's frequently nice to get the structure of a
> table without any data, ie, pull a single row with each attribute's
> value is null. I use the query (dual is a table of one row ala
> Oracle):
>
> select m.* from dual
> left join mytable m on( false );

Out of curiosity, why do it this way? Does "rownum" not get set if there
are no rows returned?

Actually, even if it doesn't why not use:
SELECT * FROM mytable WHERE true=false

Surely your client interface returns the types/column-names then? It
should - that's a set of 0 rows.

--
Richard Huxton
Archonet Ltd