resources_assing inconsitency

Select resources_assign.* 
FROM resources_assign 
LEFT JOIN termine ON (termine.termin_id = resources_assign.`assign_user_id`)
LEFT JOIN auth_user_md5 ON (auth_user_md5.user_id = resources_assign.`assign_user_id`)
WHERE auth_user_md5.user_id IS NULL
AND termine.termin_id IS NULL

Select resources_assign.*
FROM resources_assign
LEFT JOIN termine ON (termine.termin_id = resources_assign.assign_user_id)
LEFT JOIN auth_user_md5 ON (auth_user_md5.user_id = resources_assign.assign_user_id)
LEFT JOIN seminare ON (seminare.Seminar_id = termine.range_id)
WHERE auth_user_md5.user_id IS NULL
AND (termine.termin_id IS NULL OR seminare.Seminar_id IS NULL)

Select resources_assign.*
FROM resources_assign
LEFT JOIN termine ON (termine.termin_id = resources_assign.assign_user_id)
LEFT JOIN auth_user_md5 ON (auth_user_md5.user_id = resources_assign.assign_user_id)
LEFT JOIN seminare ON (seminare.Seminar_id = termine.range_id)
LEFT JOIN seminare AS s2 ON (s2.Seminar_id = resources_assign.assign_user_id)
LEFT JOIN Institute ON (Institute.Institut_id = resources_assign.assign_user_id)
WHERE auth_user_md5.user_id IS NULL
AND (termine.termin_id IS NULL OR seminare.Seminar_id IS NULL)
AND s2.Seminar_id IS NULL
AND Institute.Institut_id IS NULL