I'm having that dreaded GROUP_BY issue on a website. I suspect the server auto-updated itself or something as the site was fine before.
Now it's running on mySQL 5.7.10. The site wont load. I get the usual:
Internal Server Error CDbCommand failed to execute the SQL statement: SQLSTATE[42000]: Syntax error or access violation: 1055 Expression #18 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'creighton_mma_craft.structureelements.root' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
I followed the instructions I have used before (adding the settings into my.cnf to return the group by settings to previous behavior).
It works for a few mins, then the whole of mySQL dies. I can no longer access it at all. I can only bring it back up by removing the line and restarting mySQL. I have tried several times and get the same result each time.
WHAT ON EARTH IS HAPPENING??