DB Error: selectList query failed

SELECT SQL_CALC_FOUND_ROWS file_attachments.*, channels.name AS channel, files.name, files.ext, files.title, files.type_id, files.size FROM file_attachments LEFT JOIN files ON files.id = file_attachments.file_id LEFT JOIN channels ON channels.id = file_attachments.channel_id WHERE (channels.name = 'articles' AND object_id = AND (type_id = 1 AND main = 0))ORDER BY weight

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'AND (type_id = 1 AND main = 0))ORDER BY weight' at line 13