Re: Parethesis don't work correctly in where clause

On Thu, 2003-04-17 at 09:23, Casey Allen Shobe wrote:

> I have a query with:
> where "n"."revision" = 2
...
> However, if I add:
> and (
>         "t"."name" = 'nibc'
>     and    "n"."identifier" = 1274
> ) or (
>         "t"."name" = 'client'
>     and    "n"."identifier" = 383
> )
> PostgreSQL returns only the revision 2 tuple for nibc 1274, but also a
> revision 1 tuple for client 383.  ONLY things matching revision 2 should be
> found, but for some reason the "n"."revision" = 2 isn't being applied
> globally, but only to the first set of parenthesis.

This is simply a matter of boolean logic and the precedence of the AND
and OR operators.

If you instead force the operator precedence and add

and ((
                "t"."name" = 'nibc'
        and     "n"."identifier" = 1274
) or (
                "t"."name" = 'client'
        and     "n"."identifier" = 383
))

it should work, no?

--
Oliver Elphick                                Oliver.Elphick@lfix.co.uk
Isle of Wight, UK                             http://www.lfix.co.uk/oliver
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