MongoDB translator issues with aggregate function expressions

MongoDB queries involing expressions with aggregate functions in the select or having clauses will fail. It appears that another projection phase is needed to handling those computations as they are not valid in the group operation.

For example, these result in exceptions:

SELECT min(e1)+1, e2 FROM TIME_TEST GROUP BY e2
SELECT min(e1), e2 FROM TIME_TEST GROUP BY e2 HAVING year(e2) + count(*) = 2