Django“where子句中的未知列”，用于排除，但不用于筛选

我有一个销售模型，外键指向打印模型，外键指向衬衫模型，最后外键指向样式模型。在最后一个模型中，有一个ptype字段，它是另一个模型的外键

这些列都存在于mysql表中，它已经使用了一段时间，但我仍然进行了四次检查

这是我的代码：

sales = sales.exclude(print__shirt__style__ptype=ptype)

这给了我一个错误：

(1054, "Unknown column 'appname_prints.ptype_id' in 'where clause'")

请注意，它在打印模型中查找ptype_id字段，而不是在样式模型中。为什么它忽略了“衬衫风格”

样式模型还有一个品牌外键。我试着用brand替换ptype，只是想看看会发生什么，结果成功了。这就是变化：

sales = sales.exclude(print__shirt__style__brand=brand)

如果我将exclude更改为filter，而不更改其他内容，那么它的工作方式显然与我需要的相反

sales = sales.filter(print__shirt__style__ptype=ptype)

为了完整起见，下面也给出了相同的错误

sales = sales.filter(~Q(print__shirt__style__ptype=ptype))

以下是回溯：

Traceback:
File "/vhosts/domain.com/.virtualenvs/projectname/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  111.                         response = callback(request, *callback_args, **callback_kwargs)
File "/vhosts/domain.com/django/projectname/appname/admin_views.py" in popularity_report
  1032.     for s in sales:
File "/vhosts/domain.com/.virtualenvs/projectname/lib/python2.7/site-packages/django/db/models/query.py" in _result_iter
  118.                 self._fill_cache()
File "/vhosts/domain.com/.virtualenvs/projectname/lib/python2.7/site-packages/django/db/models/query.py" in _fill_cache
  892.                     self._result_cache.append(self._iter.next())
File "/vhosts/domain.com/.virtualenvs/projectname/lib/python2.7/site-packages/django/db/models/query.py" in iterator
  291.         for row in compiler.results_iter():
File "/vhosts/domain.com/.virtualenvs/projectname/lib/python2.7/site-packages/django/db/models/sql/compiler.py" in results_iter
  763.         for rows in self.execute_sql(MULTI):
File "/vhosts/domain.com/.virtualenvs/projectname/lib/python2.7/site-packages/django/db/models/sql/compiler.py" in execute_sql
  818.         cursor.execute(sql, params)
File "/vhosts/domain.com/.virtualenvs/projectname/lib/python2.7/site-packages/django/db/backends/util.py" in execute
  40.             return self.cursor.execute(sql, params)
File "/vhosts/domain.com/.virtualenvs/projectname/lib/python2.7/site-packages/django/db/backends/mysql/base.py" in execute
  114.             return self.cursor.execute(query, args)
File "/vhosts/domain.com/.virtualenvs/projectname/lib/python2.7/site-packages/MySQLdb/cursors.py" in execute
  201.             self.errorhandler(self, exc, value)
File "/vhosts/domain.com/.virtualenvs/projectname/lib/python2.7/site-packages/MySQLdb/connections.py" in defaulterrorhandler
  36.     raise errorclass, errorvalue

Exception Type: DatabaseError at /popularity/
Exception Value: (1054, "Unknown column 'appname_prints.ptype_id' in 'where clause'")

最后是一些版本号：

Django 1.4.5 Mysql Python 1.2.4

知道我能做什么吗