题解 | #21年8月份练题总数#

-- 方法 1
select
    count(distinct device_id) as did_cnt,
    count(question_id) as question_cnt
from
    question_practice_detail
where
    month (date) = '08';

-- 方法 2
select
    count(distinct device_id) as did_cnt,
    count(question_id) as question_cnt
from
    question_practice_detail
where
    date like '%-08-%';

-- 方法 3
select
    count(distinct device_id) as did_cnt,
    count(question_id) as question_cnt
from
    question_practice_detail
where
    substr(date,6,2)=08;