Error related to only_full_group_by when executing a query in MySql

Question

I have upgraded my system and have installed MySql 5.7.9 with php for a web application I am working on. I have a query that is dynamically created, and when run in older ve

Answer 1

This is what helped me to understand the entire issue:

1. https://stackoverflow.com/a/20074634/1066234
2. https://dev.mysql.com/doc/refman/5.7/en/group-by-handling.html

And in the following another example of a problematic query.

Problematic:

SELECT COUNT(*) as attempts, SUM(elapsed) as elapsedtotal, userid, timestamp, questionid, answerid, SUM(correct) as correct, elapsed, ipaddress FROM `gameplay`
                        WHERE timestamp >= DATE_SUB(NOW(), INTERVAL 1 DAY)
                        AND cookieid = #

Solved by adding this to the end:

  GROUP BY timestamp, userid, cookieid, questionid, answerid, elapsed, ipaddress

Note: See the error message in PHP, it tells you where the problem lies.

Example:

MySQL query error 1140: In aggregated query without GROUP BY, expression #4 of SELECT list contains nonaggregated column 'db.gameplay.timestamp'; this is incompatible with sql_mode=only_full_group_by - Query: SELECT COUNT(*) as attempts, SUM(elapsed) as elapsedtotal, userid, timestamp, questionid, answerid, SUM(correct) as correct, elapsed, ipaddress FROM gameplay WHERE timestamp >= DATE_SUB(NOW(), INTERVAL 1 DAY) AND userid = 1

In this case, expression #4 was missing in the GROUP BY.