That looks like a good try, but there is more you should know.
The Data Explorer plugin has built in LIMIT so time and memory consuming queries won’t cause a bog down.
“approved” is like a boolean true / false field so ordering by it is mostly useless.
IMHO it would be more useful and more efficient to ORDER BY the indexed id field.
Try these
SELECT COUNT(`website`)
FROM `user_profiles`
WHERE `website` IS NOT NULL;
and
SELECT COUNT(`bio_raw`)
FROM `user_profiles`
WHERE `bio_raw` IS NOT NULL;
to get an idea of how many rows you’re dealing with.