解决Mysql：1055 – Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated

解决：

方法一：修改配置。去掉ONLY_FULL_GROUP_BY

如果是Linux，就在配置文件（my.cnf）中修改 sql_mode 的配置（在/usr/local/etc/my.cnf路径下）并重启mysql服务。

$ vim /usr/local/etc/my.cnf
sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

set @@sql_mode 
='STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';

如果要永久生效需要在MySQL的my.ini配置文件中去修改：

在[mysqld]下添加sql_mode=’STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION’，然后保存并重启服务。