Please test the stuff you submit. You should use `'` instead of `
```
$findShares = \OC_DB::prepare('SELECT `file_source` FROM `*PREFIX*share` LEFT JOIN `*PREFIX*filecache` ON `file_source` = `*PREFIX*filecache`.`fileid` WHERE `*PREFIX*filecache`.`fileid` IS NULL AND `*PREFIX*share`.`item_type` IN (\'file\', \'folder\')');
```