Q&A for pro webmasters
WITH LittlePosts(Id,PostTypeId,ParentId) AS ( SELECT 1,1,NULL UNION ALL SELECT 2,1,NULL UNION ALL SELECT 3,2,1 UNION ALL SELECT 4,2,2 UNION ALL SELECT 5,2,2 UNION ALL SELECT 7,1,NULL ) SELECT Q.Id, A.ID FROM (LittlePosts AS Q JOIN Posts AS A ON Q.Id = A.ParentId) /*SELECT Id, ( SELECT COUNT(*) FROM LittlePosts AS C WHERE C.ParentId = P.Id AND C.PostTypeId = 2 ) AS NumAnswers FROM LittlePosts P WHERE PostTypeId=1; */