Python 通过二次模型关系进行注释

我有以下（简化）模型：

我想做的是获得一份学校名单，注明每所学校的职位数量。出于许多原因，Post是外键输入到UserProfile的，而不是学校。我将如何使用Django ORM来执行此操作？我猜我必须使用annotate（），但当所讨论的两个模型没有外键直接关联时，它似乎不起作用。

用于：

将使用以下sql：

SELECT "testapp_school"."id", "testapp_school"."name", COUNT("testapp_post"."id") AS "post_count" FROM "testapp_school" LEFT OUTER JOIN "testapp_userprofile" ON ("testapp_school"."id" = "testapp_userprofile"."school_id") LEFT OUTER JOIN "testapp_post" ON ("testapp_userprofile"."id" = "testapp_post"."profile_id") GROUP BY "testapp_school"."id", "testapp_school"."name", "testapp_school"."id", "testapp_school"."name" LIMIT 21;

用于：

将使用以下sql：

SELECT "testapp_school"."id", "testapp_school"."name", COUNT("testapp_post"."id") AS "post_count" FROM "testapp_school" LEFT OUTER JOIN "testapp_userprofile" ON ("testapp_school"."id" = "testapp_userprofile"."school_id") LEFT OUTER JOIN "testapp_post" ON ("testapp_userprofile"."id" = "testapp_post"."profile_id") GROUP BY "testapp_school"."id", "testapp_school"."name", "testapp_school"."id", "testapp_school"."name" LIMIT 21;

---

头脑=崩溃。非常感谢！既然Post被设置为UserProfile，而不是双下划线语法所暗示的那样，那么为什么这样做呢？因为这种关系是这样工作的：school\uuuuu UserProfile\uuuu Post。我们省略了school，因为这是一个school查询集。头脑=崩溃。非常感谢！既然Post被设置为UserProfile，而不是双下划线语法所暗示的那样，那么为什么这样做呢？因为这种关系是这样工作的：school\uuuuu UserProfile\uuuu Post。我们省略了school，因为这是一个school查询集。

SELECT "testapp_school"."id", "testapp_school"."name", COUNT("testapp_post"."id") AS "post_count" FROM "testapp_school" LEFT OUTER JOIN "testapp_userprofile" ON ("testapp_school"."id" = "testapp_userprofile"."school_id") LEFT OUTER JOIN "testapp_post" ON ("testapp_userprofile"."id" = "testapp_post"."profile_id") GROUP BY "testapp_school"."id", "testapp_school"."name", "testapp_school"."id", "testapp_school"."name" LIMIT 21;