yesterday I saw some invalid MySQL queries in my logs:
SELECT ObjectCustomFieldValues_1.Content AS col0, COUNT(main.id) AS id
FROM Tickets main
LEFT JOIN ObjectCustomFieldValues ObjectCustomFieldValues_1
ON ( ObjectCustomFieldValues_1.CustomField = ‘90’ )
AND ( ObjectCustomFieldValues_1.Disabled = ‘0’ )
AND ( ObjectCustomFieldValues_1.ObjectType = ‘RT::Ticket’ )
AND ( ObjectCustomFieldValues_1.ObjectId = main.id )
WHERE (main.Id IN ())
GROUP BY ObjectCustomFieldValues_1.Content
I think this comes from .
Recently there was also a branch merged  where you switched from
looping over value lists to using the IN operator.
May there need to be a check that the VALUE list is not empty to avoid
invalid SQL queries?