Mysql解决SELECT list is not in GROUP BY clause and contains nonaggregated column 问题

在使用GROUP BY对Mysql的数据表进行查询时如果出现以下错误

select * from user group by age;

ERROR 1055 (42000): Expression #1 of SELECT list is not in GROUP BY clause 
and contains nonaggregated column 'test.user.user_id' which is not 
functionally dependent on columns  in GROUP BY clause; this is 
incompatible with sql_mode=only_full_group_by

解决办法：
1.查询mysql 相关mode

select @@global.sql_mode;

可以看到模式中包含了ONLY_FULL_GROUP_BY，只要没有这个配置即可。
我的Mysql版本是5.7.21，默认是带了ONLY_FULL_GROUP_BY模式。

 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 

2.重设模式值

set @@global.sql_mode=`STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE, 
ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION`;

3.重启Mysql即可