WITH ### 每个月用户的 monthly_practices_u AS( SELECT device_id,DATE_format(event_date,'%Y-%m') ym,COUNT(question_id) m_user_cnt FROM question_practice_detail GROUP BY DATE_format(event_date,'%Y-%m'),device_id ), ### 每个月总的 monthly_practices AS( SELECT DATE_format(event_date,'%Y-%m') ym,COUNT(question_id) m...