1.背景
mysql库中写联合查询语句时报错，055 - Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column ‘xxxx.xxx’ which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
2.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。（5.7.5之前，MySQL没有检测到功能依赖关系，默认情况下不启用ONLY_FULL_GROUP_BY
可以在命令行，查询验证：
>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
3.解决
去掉ONLY_FULL_GROUP_BY选项即可，即：
>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';
4.其它
3中实际的修改，要看你查询出来的结果。