This type of thing has been asked a few times before, but is not quite what I am looking for. I need to SET two rows equal to different parts of a subquery.
You can simply join the table in a subquery that do some calculations,
UPDATE records a
INNER JOIN
(
SELECT blah,
COUNT(*) totalCount,
SUM(amount) totalSum
FROM leads_table
GROUP BY blah
) b ON b.blah = a.blah
SET a.leads = b.totalCount
a.earnings = b.totalSum