summer2077

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题解 | #今年的第几天？#

between 也可以匹配日期 select count(distinct device_id) as did_cnt, count(question_id) as question_cnt from question_practice_detail where date betw...

Mysql

2022-01-27

6 977

题解 | #21年8月份练题总数#

我个人觉得遇到这种模糊查询，like 关键字特别好用，下面是使用 like 关键字查询的题解： SELECT DAY(date) day, COUNT(question_id) question_cnt FROM question_practice_detail WHERE date like '%...

Mysql

2021-10-21

253 4367

题解 | #统计每种性别的人数#

转自https://www.cnblogs.com/mqxs/p/7380933.html （1）SUBSTRING_INDEX的写法 SELECT SUBSTRING_INDEX(profile,",",-1) gender,COUNT(*) number FROM user_...

Mysql

2021-09-28

646 11185