给数据库升了个级，后台纷纷报错误：

报错信息：

Expression #1 of ORDER BY clause is not in SELECT list, references column 'xxxx' which is not in SELECT list; this is incompatible with DISTINCT

问题原因：

mysql5.7.34及以上版本将sql_mode的ONLY_FULL_GROUP_BY模式默认设置为打开状态，会导致一些错误：

1、我们使用GROUP BY查询时，出现在SELECT字段后面的只能是GROUP BY后面的分组字段，或使用聚合函数包裹着的字段，否则会报错如下信息：

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

2、当使用ORDER BY查询时，不能使用SELECT DISTINCT去重查询。否则会报错如下信息：

   Expression #1 of ORDER BY clause is not in SELECT list, 
   references column 'database.table.column' which is not in SELECT list; 
   this is incompatible with DISTINCT

查询验证：

select version(); 查询版本
select @@global.sql_mode   查询sql_mode

解决方法：

去除ONLY_FULL_GROUP_BY

1、通过命令关闭：

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’;
但该方法在重启Mysql服务后会失效，重启服务后会失效

2、通过修改mysql的配置文件关闭ONLY_FULL_GROUP_BY SQL模式

sudo vim /etc/mysql/conf.d/mysql.cnf

文件底部追加:

[mysqld]
sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

保存并重启mysql

sudo service mysql restart