在MySQL8中使用group by引發的問題：1 of SELECT list is not in GROUP BY clause

出現的問題

當在SQL中使用group by時可能會出現如下問題：

> 1055 - 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 clause; this is incompatible with sql_mode=only_full_group_by

解決辦法

嘗試解決，一般是在my.cnf文件下的[mysqld]中加入如下內容：

sql_mode='NO_AUTO_VALUE_ON_ZERO,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,
ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION,PIPES_AS_CONCAT,ANSI_QUOTES'

然後重啓數據庫，可能會啓不來，原因是MYSQL8以上已經取消了NO_AUTO_CREATE_USER，sql_mode中不能包含這個，將其去掉再次啓動MySQL即可。