MySQL INSERT SELECT. Ordering insert by count but don't actually insert the count number

Sorry for the ridicu开发者_如何转开发lous title!

Is it possible to run a MySQL INSERT SELECT query where the 'SELECT' portion includes a COUNT() function (to benefit from a HAVING clause) -- this creates an unmatching column count on the INSERT portion.

For example:

INSERT INTO my_log (user_id, date_finished) 
SELECT COUNT(id) AS count, user_id, '2011-05-31 00:00:00'
FROM assignments WHERE assignment_type = 10 
GROUP BY user_id
HAVING count >=10 

I want to insert into the TABLE my_log a date for users who've completed 10 assignments of the type 10. In reality I'm expanding on this slightly so it's important I use the COUNT and HAVING to find only users who have completed 10 or more assignments. But my problem remains that I'm trying to insert 3 columns into a declared 2 columns because of the COUNT() function, so I'm looking for a way to benefit from the COUNT but not return it in my data set / considered in the insertion.

Thanks for any help :)

Try with:

INSERT INTO my_log ( user_id, date_finished) 
SELECT user_id, '2011-05-31 00:00:00'
FROM assignments WHERE assignment_type = 10 
GROUP BY user_id
HAVING ( COUNT(id) ) >=10