Disable ONLY_FULL_GROUP_BY
sudo nano /etc/mysql/my.cnf
Add this to the end of the file
[mysqld]
sql_mode = "STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
sudo service mysql restart to restart MySQL