用到GROUP BY 语句查询时com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column ‘col_user_6.a.START_TIME‘ which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by错误

解决方法 (修改全局)：执行set global   sql_mode = ‘‘; 把sql_mode 改成非only_full_group_by模式。验证是否生效 SELECT @@GLOBAL.sql_mode 或 SELECT @@sql_mode

执行（只是修改会话级别的，只是当前会话生效）set  session sql_mode = ‘‘; 把sql_mode 改成非only_full_group_by模式。验证是否生效 SELECT @@GLOBAL.sql_mode 或 SELECT @@sql_mode

九、MySQL 5.7.9版本sql_mode=only_full_group_by问题

原文：https://www.cnblogs.com/feifeifeisir/p/9827680.html