Python django在顺序_上使用条件表达式的正确方法

我使用的是来自条件表达式示例文档，我在SO to order上找到了一些答案，通过

status\u text

或

status

，在这个示例中我使用了

status\u text

字段。我在我的api

get_queryset

中做了所有这些，我做了类似的事情

def get_queryset(self):
    queryset = LeadContact.objects.none()
    user = self.request.user
    # I have some other conditions here

    # This is the conditional expressions that I'm building for order_by
    case_sql = LeadContact.objects.annotate(
        custom_order=Case(
            When(status_text=LeadContactConstants.STATUS_CLIENT, then=Value(1)),
            When(status_text=LeadContactConstants.STATUS_QUALIFIED, then=Value(2)),
            When(status_text=LeadContactConstants.STATUS_CONTACTED, then=Value(3)),
            When(status_text=LeadContactConstants.STATUS_PRISTINE, then=Value(4)),
            output_field=CharField(),
        )
    ).order_by('custom_order')

    return queryset.extra(select={'status_text': case_sql}, order_by=['status_text'])

现在数据库正在抛出此回溯：

Traceback:

    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
      132.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/views/decorators/csrf.py" in wrapped_view
      58.         return view_func(*args, **kwargs)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/rest_framework/viewsets.py" in view
      87.             return self.dispatch(request, *args, **kwargs)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/rest_framework/views.py" in dispatch
      466.             response = self.handle_exception(exc)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/rest_framework/views.py" in dispatch
      463.             response = handler(request, *args, **kwargs)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/rest_framework/mixins.py" in list
      42.         page = self.paginate_queryset(queryset)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/rest_framework/generics.py" in paginate_queryset
      172.         return self.paginator.paginate_queryset(queryset, self.request, view=self)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/rest_framework/pagination.py" in paginate_queryset
      303.         return list(queryset[self.offset:self.offset + self.limit])
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/db/models/query.py" in __iter__
      162.         self._fetch_all()
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/db/models/query.py" in _fetch_all
      965.             self._result_cache = list(self.iterator())
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/db/models/query.py" in iterator
      238.         results = compiler.execute_sql()
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py" in execute_sql
      840.             cursor.execute(sql, params)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/db/backends/utils.py" in execute
      79.             return super(CursorDebugWrapper, self).execute(sql, params)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/db/backends/utils.py" in execute
      64.                 return self.cursor.execute(sql, params)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/db/utils.py" in __exit__
      98.                 six.reraise(dj_exc_type, dj_exc_value, traceback)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/db/backends/utils.py" in execute
      64.                 return self.cursor.execute(sql, params)
    File "/home/vagrant/virtualenv/local/lib/python2.7/site-packages/django/db/backends/mysql/base.py" in execute
      124.             return self.cursor.execute(query, args)
    File "build/bdist.linux-x86_64/egg/MySQLdb/cursors.py" in execute
      205.             self.errorhandler(self, exc, value)
    File "build/bdist.linux-x86_64/egg/MySQLdb/connections.py" in defaulterrorhandler
      36.     raise errorclass, errorvalue

    Exception Type: ProgrammingError at /api/sales/lead_contact/
    Exception Value: (1064, "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 '[<LeadContact: Liam Higgins>, <LeadContact: Juraj  Polerecky>, <LeadContact: Pau' at line 1")

而

LeadContactConstants

模型是：

class LeadContactConstants(object):
    STATUS_PRISTINE = "PRISTINE"
    STATUS_CONTACTED = "CONTACTED"
    STATUS_QUALIFIED = "QUALIFIED"
    STATUS_CLIENT = "CLIENT"

    STATUSES = ((STATUS_PRISTINE, "Virgin"),
                (STATUS_CONTACTED, "Contacted"),
                (STATUS_QUALIFIED, "Qualified"),
                (STATUS_CLIENT, "Client"))

---

我不知道如何处理这个问题，所以有人能告诉我发生了什么，我如何解决这个问题，这样我就可以正确地订购我的联系人了，谢谢。

我不明白你为什么要把它传递给

.extra（）

。这不是它的工作原理：

case\u sql

是查询集本身，您应该返回它。

我不明白您为什么要将它传递给

.extra（）

。这不是它的工作原理：

case\u sql

是查询集本身，你应该直接返回它。

好吧，我误解了文档中的一些内容，但是现在订单正在将我的

状态从值变为数字，当我转到
return.order\u by（'case\u sql'）
时，它仍然没有排序，我还做错了什么我会接受答案，但我仍在解决为什么这会将我的
status\u text
更改为numberrok我误解了文档中的一些内容，但现在订单将我的
status\u text
更改为值中的数字，它仍然没有排序，当我转到“return.order\u by（'case\u sql'）

时，我在这里还做错了什么我会接受答案，但我仍在解决为什么这会将我的

状态\u text

更改为数字

class LeadContactConstants(object):
    STATUS_PRISTINE = "PRISTINE"
    STATUS_CONTACTED = "CONTACTED"
    STATUS_QUALIFIED = "QUALIFIED"
    STATUS_CLIENT = "CLIENT"

    STATUSES = ((STATUS_PRISTINE, "Virgin"),
                (STATUS_CONTACTED, "Contacted"),
                (STATUS_QUALIFIED, "Qualified"),
                (STATUS_CLIENT, "Client"))