MySQL解决Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column问题

在使用MySQL进行嵌套查询的时候遇见了错误：

MySQL语句：

select *, count(id) as cnt from (select * from message order by created_date desc) tt group by conversation_id ;

错误：

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

出现该错误的原因：

MySQL 5.7.5及以上功能依赖检测功能。如果启用了ONLY_FULL_GROUP_BY SQL模式（默认情况下），MySQL将拒绝选择列表，HAVING条件或ORDER BY列表的查询引用在GROUP BY子句中既未命名的非集合列，也不在功能上依赖于它们

解决：

解决办法： 

1.查询mysql 相关mode

select @@global.sql_mode;

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 

可以看到模式中包含了ONLY_FULL_GROUP_BY，只要没有这个配置即可。 

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