MySQL group 时遇到非聚集的（nonaggregated）是什么鬼？

在数据库查询使用 group by 子句时，蹦出来这个错误：

Syntax error or access violation: 1055 Expression #3 of SELECT list is not in GROUP BY clause and contains nonaggregated

解决办法：

sudo mysql -uroot -p
mysql > SET GLOBAL sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY',''));

详见：https://stackoverflow.com/a/41145619/3054511