MySQL8 提示1055 错误代码

问题产生场景：今天使用Python3+PyMYSQL + SQLAlchemy  执行分组查询提示如下错误信息：

sqlalchemy.exc.OperationalError: (pymysql.err.OperationalError) (1055, "Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'hotel.users.id' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by") 
[SQL: SELECT users.id AS users_id, users.name AS users_name, users.age AS users_age, users.email AS users_email, users.ctime AS users_ctime, users.extra AS users_extra  
FROM users GROUP BY users.extra]

解决办法：

1. 

在不删除现有模式的情况下，只向sql_mode添加一种模式：

SET sql_mode=(SELECT CONCAT(@@sql_mode,',<mode_to_add>'));

2.
仅从sql_mode中删除特定模式而不删除其他模式：

SET sql_mode=(SELECT REPLACE(@@sql_mode,'<mode_to_remove>',''));

3.
在您的情况下，如果您只想删除ONLY_FULL_GROUP_BY模式，请使用以下命令：

SET sql_mode=(SELECT REPLACE(@@sql_mode, 'ONLY_FULL_GROUP_BY', ''));

我选择的是第3 个方案,直接删除 only_full_group_by

# 查询当前MySQL支持模式 
select version(),@@sql_mode;  
# 移除ONLY_FULL_GROUP_BY 模式 
SET sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY',''));