ccnn_yanan的博客

首先联合索引 (a,b,c)相当于 a, ab, abc 建立了三个索引 反正就是中间不能断不要一味的建联合 索引 要看他xuan'ze'xi

spring: shardingsphere: datasource: names: m0,m1,m2,m3 m0: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://124.70.133.147:3306/saas_cms_0?useUnicode=true..

时间字符换比较SELECT count(1) FROM article where STR_TO_DATE(create_time,'%Y-%m-%d %H:%i:%s') > STR_TO_DATE('2019-10-17 08:00:40','%Y-%m-%d %H:%i:%s')查询出重复的记录select channel_code,count(*) as count fr...