I wanted to disable the ONLY_FULL_GROUP_BY value of sql-mode permanently even restart the MySQL server. following things I have tried to do but which are not working. that set to the default value when restarting the MySQL.
>Solution :
Persisted settings are permanent. They apply across server restarts.
set PERSIST sql_mode='STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION';
have you tried this?