instruction: Total questions and answers per calendar month.
response: SELECT TIME_TO_STR(CreationDate, '%Y') * 100 + TIME_TO_STR(CreationDate, '%m') AS YearMonth, SUM(CASE WHEN ParentId IS NULL THEN 1 ELSE 0 END) AS TotalQuestions, SUM(CASE WHEN NOT ParentId IS NULL THEN 1 ELSE 0 END) AS TotalAnswers FROM Posts GROUP BY TIME_TO_STR(CreationDate, '%Y'), TIME_TO_STR(CreationDate, '%m') ORDER BY TIME_TO_STR(CreationDate, '%Y'), TIME_TO_STR(CreationDate, '%m')