###HUMAN: questions answers per hour for user., ###ASSISTANT: SELECT TIME_TO_STR(CreationDate, '%h') AS hour, COUNT(CASE WHEN PostTypeId = 1 THEN 1 END) AS questions, COUNT(CASE WHEN PostTypeId = 2 THEN 1 END) AS answers FROM Posts WHERE PostTypeId IN (1, 2) GROUP BY TIME_TO_STR(CreationDate, '%h')