[kgroneman]

I found it! Thanks to your help and guidance:

SELECT COUNT(postid) AS count, user.username
FROM post
LEFT JOIN user ON (user.userid = post.userid)
WHERE (dateline > UNIX_TIMESTAMP('2015-06-31') AND dateline < UNIX_TIMESTAMP('2015-10-01'))
AND user.usergroupid IN (10)
GROUP BY post.username
ORDER BY count
DESC

It does just what I want. Thanks so much for taking the time to respond.

--------------- Added [DATE]1445289865[/DATE] at [TIME]1445289865[/TIME] ---------------

Ok, one last (I hope) question: How do I get email addresses to also show along with the user ID in the resultant list?