EXCEPT call not working - Mailing list pgsql-general

From chris mutchler
Subject EXCEPT call not working
Date
Msg-id Pine.BSF.4.10.10009071457430.14802-100000@leibnizcreations.com
Whole thread Raw
Responses Re: EXCEPT call not working  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
I have a perl script that interacts with my postgresql server through the
DBI module.  When, I send my query to the server it will work fine with
the following:

$sth = $dbh->prepare("
        SELECT p.ids_name, m.start_time, m.end_time
        FROM mail_schedule m, personnel p
        WHERE p.ids_int = m.ids_int AND
        m.dow = $weekday
        UNION
        SELECT p.ids_name, c.on_start, c.on_end
        FROM mail_changes c, personnel p
        WHERE p.ids_int = c.ids_int
");

But as soon as I place the EXCEPT call in there it stops working and
doesn't return any values:

$sth = $dbh->prepare("
        SELECT p.ids_name, m.start_time, m.end_time
        FROM mail_schedule m, personnel p
        WHERE p.ids_int = m.ids_int AND
        m.dow = $weekday
        UNION
        SELECT p.ids_name, c.on_start, c.on_end
        FROM mail_changes c, personnel p
        WHERE p.ids_int = c.ids_int
        EXCEPT
        SELECT p.ids_name, c.on_start, c.on_end
        FROM mail_changes c, personnel p
        WHERE p.ids_int = c.ids_int
        AND c.on_start = 0
        AND c.on_end = 0
");

Does anyone have any suggestions as to why my EXCEPT call isn't working?
If you see some drastic or subtle syntax error let me know.  I have never
used EXCEPT before, and am not having much luck.  thanks.

Chris Mutchler
davron@leibnizcreations.com


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