Recently I have updated one of my server MySQL, then I have found that old MySQL Group By Query is not running anymore. It happens because of  notorious nonstandard MySQL extension to GROUP BY

Go To Mysql console:

Type the below command & see what are current SQL mode:

SELECT @@GLOBAL.sql_mode;

Type the below command to see what SQL mode is running from session, because even you set Global SQL mode, mysql run Session SQL mode until it is not restarted:

SELECT @@SESSION.sql_mode;

Now Run the below commands to set server MYSQL instance Mode:

SET GLOBAL sql_mode = 'NO_ENGINE_SUBSTITUTION';
SET SESSION sql_mode = 'NO_ENGINE_SUBSTITUTION';

ForReference: https://stackoverflow.com/questions/37089347/is-there-any-value-capability-for-mysql-5-6