SQL39题解 | #21年8月份练题总数#

#练习总题数: COUNT(questiono_id)
#八月份练习总题数:SUM( IF( YEAR(date)=21 AND MONTH(DATE) = 8, 1 ,0))
SELECT  COUNT(DISTINCT device_id) AS did_cnt,
        COUNT(question_id) AS question_cnt
FROM question_practice_detail
WHERE date like '2021-08%';