问题描述
报错:
ERROR 1055 (42000): Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'database_tl.emp.id' which is not functionally dependent on columns in GROUP BY clause;
this is incompatible with sql_mode=only_full_group_by
原因
对于GROUP BY聚合操作,如果在SELECT中的列,没有在GROUP BY中出现,那么这个SQL是不合法的,因为列不在GROUP BY从句中,也就是说查出来的列必须在group by后面出现否则就会报错,或者这个字段出现在聚合函数里面。
解决问题
检查版本
登陆mysql客户端
mysql> select version(); +-----------+ | version() | +-----------+ | 5.7.21 | +-----------+ 1 row in set (0.00 sec)
mysql> select @@GLOBAL.sql_mode; +-------------------------------------------------------------------------------------------------------------------------------------------+ | @@GLOBAL.sql_mode | +-------------------------------------------------------------------------------------------------------------------------------------------+ | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION | +-------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)
看到上面反悔的命令行第一段---> ONLY_FULL_GROUP_BY;
网上给出很多解决办法,经我的尝试,有时是不起作用;
彻底解决办法:
找到mysql的my.cnf文件在[mysqld]下边加入:
[mysqld] character-set-server=utf8 max_connections=1000 sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
重启MySQL数据库就好了