I'm sure there is ... here's one way I can think of, a two-step
process but doable in 3.23 I think. Use a server-side variable and a
combination of the LIMIT and OFFSET features.
SELECT id FROM items ORDER BY DATE DESC LIMIT 1 OFFSET 10 INTO @myid
then
SELECT AVG(cost)
FROM items
WHERE id >= @
Yes, the LIMIT function affects number of rows returned, not number of
rows evaluated.
If you're on 4.1 or later, you could use a subselect. Assuming you
have an ID field in your table, something like this:
SELECT AVG(cost)
FROM items
WHERE id IN (SELECT id FROM items ORDER BY date DESC LIMIT 1
