instruction: Q's with no A's >= 0 after three months. Finds number of questions that have no accepted answer and no answers with a score >= 0 after three months
response: SELECT COUNT(*), MIN(CreationDate), MAX(CreationDate), COUNT(DISTINCT OwnerUserId) FROM Posts AS q WHERE PostTypeId = 1 AND Score < 1 AND CreationDate < DATEADD(MONTH, -3, GETDATE()) AND ClosedDate IS NULL AND AcceptedAnswerId IS NULL AND NOT EXISTS(SELECT * FROM Posts AS a WHERE PostTypeId = 2 AND ParentId = q.Id AND Score >= 0)