gunnar wrote: > The subquery will always return one result or no result. So I only > have to UNION it ALL with the SELECT NULL part.
>>> Clemens Ladisch <clemens at ladisch.de> wrote: >>>> ... WHERE cb_seq_num > ( >>>> SELECT cb_seq_num >>>> FROM ordercallback >>>> WHERE cb_uuid=@CBUUID >>>> UNION ALL >>>> SELECT NULL -- at least one result >>>> LIMIT 1) -- at most one result But with the SELECT NULL, the subquery now returns one or two results. If you do use the UNION ALL, you also need the LIMIT. Regards, Clemens
