mysql 8 查询报错(sql_mode=only_full_group_by)

Expression #1 of ORDER BY clause is not in GROUP BY clause and contains nonaggregated column 'information_schema.PROFILING.SEQ' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

mysql 5.7之后，查询如下:
　　select @@sql_mode;
　　如果: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
默认设置了:
　　sql_mode=only_full_group_by
　　only_full_group_by:使用它就和oracle一样的group规则，select的列都要在group中，或本身就是聚合列(sum,avg,max,min)才行，只要把它去掉即可。

处理方法：直接在Mysql配置文件中去掉该设置。

sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

常用查询：

查询服务器运行状态
SHOW STATUS LIKE 'Thread%';

查看所有连接的状态
SHOW FULL PROCESSLIST

查询服务器的各种设置
SHOW VARIABLES LIKE 'max%';

临时设置最大连接数(重启会失效)
SET GLOBAL max_connections = 500