Hi Benjamin, thanks for the reply.
>> INSERT INTO D
>> SELECT a.*
>> FROM a NATURAL LEFT JOIN b NATURAL LEFT JOIN c
>> WHERE b.some_id IS NULL AND c.some_id IS NULL
>> ORDER BY a.time DESC
>> LIMIT 1000;
Benjamin> Yes, this should be correct. Why didn't you just try?
My tables contain over 50 million entries *each*, and I couldn't weigh
down the server. But I ended up making some mock tables and trying it
out. That confirmed my questions about syntax. But I also wanted to
get some advice like "you really should use a temp table for this" or
"yes, that is the best way to do it, don't bother using a temp table"
or something. I really can't test various methods for performance!