Thanks for your helpful response. Michael Glaesemann wrote: > I don't seem to have a problem with the ordering given your data. I'm > not sure why you're doing right and left joins, though. You might want > to use left joins if you have NULL id1 or id2, but otherwise just plain > JOIN should work fine. I've included both your SELECT (slightly modified > to avoid using key words) and how I'd probably right the statement.
id1 will always have a value but id2 can be NULL. So should I do a left JOIN on id2 but a plain JOIN on id1? Is there a disadvantage to using a left JOIN where it is not necessary? Adam
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