Of course, that's not legal 7.3.4 syntax. These are both too slow due to sequential scan of table:
delete from mytable where key in ( select key from mytable where posteddatetime < now() - '90 days' limit 100);
Upgrade to 7.4 - the query above will be vastly faster.
delete from mytable where exists ( select m.key from mytable m where m.key = mytable.key and m.posteddatetime < now() - '90 days' limit 100);
That one I used to use on 7.3 - I seem to recall it indexed nicely.
Chris
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