MySQL 5.7 breaks WAD Collector

[asch99]

MySQL 5.7 sets the flag ONLY_FULL_GROUP_BY in sql mode. This breaks parts of the web interface, but also the WAD Collector and possibly other WAD Services. Ideally the afflicted services and parts of the interface should be fixed.

Alternatively the ONLY_FULL_GROUP_BY can be disabled. On Ubuntu 16 this can be done by editing /etc/mysql/my.cnf. In my case the needed changes are the following additions at 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"