詳細錯誤：
在瀏覽器請求接口時
There was an unexpected error (type=Internal Server Error, status=500). could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet
查看console中錯誤：
clause and contains nonaggregated column ...
.which is not functionally dependent on columns in GROUP BY clause;
this is incompatible with sql_mode=only_full_group_by
錯誤原因：對于GROUP BY聚合操作，如果在SELECT中的列，沒有在GROUP BY中出現(xiàn)，那么這個SQL是不合法的；
解決辦法：1、檢測MySQL版本：select @@version;（我的MySQL版本是5.7.24）
2、（關(guān)掉ONLY_FULL_GROUP_BY），輸入命令
一、
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';
set session 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、重啟MySQL(很重要！！！！)；
參考：https://blog.csdn.net/yalishadaa/article/details/72861737
https://blog.csdn.net/fansili/article/details/78664267
