SQL error when searching in for tags in CP

[joostwaaijer]

We are experiencing difficulties with searching in the Tags table on the Control Panel, when the 'enableUsage' setting is enabled.

First of all, this line throws an error when trying to search: TagQuery.php#L41
Which can be fixed by replacing strtoupper($this->query->select[0]) to strtoupper(array_values($this->query)->select[0])

But after fixing that, we get an SQL error, that the subquery has more selects than it should have. This mainly comes down to the fact that when searching, the parent query is selecting from de searchindexes table and not the elements table, which is now the subquery.

In the meantime we have disabled the usage setting, so we can search in the table.