I accidentally enabled ONLY_FULL_GROUP_BY mode like this:
SET sql_mode = \'ONLY_FULL_GROUP_BY\';
How do I disable it?
Here is my solution changing the Mysql configuration through the phpmyadmin dashboard:
In order to fix "this is incompatible with sql_mode=only_full_group_by": Open phpmyadmin and goto Home Page and select 'Variables' submenu. Scroll down to find sql mode. Edit sql mode and remove 'ONLY_FULL_GROUP_BY' Save it.