Re: "left join" not working? - Mailing list pgsql-sql

On Fri, Feb 12, 2010 at 11:35:02AM -0000, Oliveiros C, wrote:
> My first guess is that
> NULL fails the condition on your WHERE clause,
> p.id_line = 1
> 
> So your WHERE clause introduces an additional level of filtering
> that filters out the NULLs coming from the LEFT JOIN...

So, if I understand correctly, a WHERE filters all results regardless of
join conditions and can turn an OUTER JOIN into an INNER JOIN.

Thanks for pointing that out!