which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mod

在进行按组查询的时候，报错

-- 按分组查询
select * from my_student group by class_id;

Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'mydatabase1.my_student.stu_id' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

在确认不是拼写错误之后，找到原因：在sql_mode里面，group by 与 only_full_group_by 不兼容。

在my.ini 文件里，修改sql_mode的值

 

并重启mysql服务

 

再重新输入语句，查询正常！