I just updated from 4.6.3 to 4.6.5, on Joomla. I have a number of Smart Groups which worked fine before, but now inconsistently fail to load contacts or settings, giving a database error instead. The error seems related to building the cache, so I assume the inconsistency comes from whether or not it's refreshing the cache entry.
The database query that causes problems is:
SELECT id, cache_date, saved_search_id, children FROM civicrm_group WHERE id 0 AND ( saved_search_id != 0 OR saved_search_id IS NOT NULL OR children IS NOT NULL )
Clearly "WHERE id 0" is invalid syntax. The problem seems to be with changes to the CRM/Contact/BAO/Query.php code. The function addGroupContactCache used to create a clause within the function, something like "WHERE ID IN (4, 7, 10)". Now it calls self::buildClause.
From some debugging I did, buildClause is usually called with "IN" as the $op value, in which case it generates a valid clause. But sometimes the $op value is "=", and it returns that "id 0" clause which breaks things.
The code changes between 4.6.3 and 4.6.5 are complicated enough that I'm not sure how to quick-fix it. Any suggestions to get our smart groups working again are very welcome!