随笔分类 -  mysql

mysql中int、bigint、smallint 和 tinyint四种数据类型
摘要：最近在做数据库表设计的时候，对于多种数字的数据类型的选择存在很多顾虑，不是很清楚到底如何选择。总结一下int、bigint、smallint 和 tinyint四种数据类型。 阅读全文
posted @ 2019-10-28 10:14 Java_lively 阅读(15340) 评论(0) 推荐(1)
数据库多表连接查询中使用group by分组语句，Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'XXX' which is not functionally dependent on columns in GROUP BY claus
摘要：需求描述： 要是用两表联合查询，并对查询的结果进行分组：sql如下： 这样的sql语句会报错结果如下： Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'a.id' wh 阅读全文
posted @ 2019-10-23 10:06 Java_lively 阅读(1613) 评论(0) 推荐(0)