Re: Please some help on a join question with sum

On Sat, 2003-04-19 at 19:52, Oliver Elphick wrote:

> SELECT aa.id,
>        aa.seqno,
>        aa.price + (
>                    SELECT SUM(bb.price)
>                      FROM bb
>                     WHERE bb.id = aa.id AND bb.seqno = aa.seqno
>                   ) AS price
>   FROM aa;

If there aren't any matching records in bb, this won't work because the
sub-select will produce null, so it should actually be:

SELECT aa.id,
       aa.seqno,
       aa.price + COALESCE(
                     (SELECT SUM(bb.price)
                        FROM bb
                       WHERE bb.id = aa.id AND bb.seqno = aa.seqno),
                  0) AS price
  FROM aa;

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