Re: [GENERAL] Negating the list of selected rows of a join

Clark Evans <clark(dot)evans(at)manhattanproject(dot)com>:

> Manuel Lemos wrote:
> > How can I make a query that works the way I want all the time, even for the
> > case when table_b is empty?
>
> SELECT table_a.name, table_a.age
> FROM table_a
> WHERE NOT EXISTS (
> SELECT 'x'
> FROM table_b
> WHERE table_b.name = table_a.name
> );
>
> Hope this will do the trick.

Maybe not -- doesn't that mean, that the query won't return a single
row in case there is *any* pair of equal names in both tables?!

Have a nice (sun)day,
Ulf

--
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Ulf Mehlig <umehlig(at)zmt(dot)uni-bremen(dot)de>
Center for Tropical Marine Ecology/ZMT, Bremen, Germany
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