选择时的Django案例

Question

我使用原始SQL作为子查询来实现结果。但是，如果我通过带注释的字段进行过滤，则会引发连接到错误（或未声明）别名的错误，如下所示：

django.db.utils.ProgrammingError: invalid reference to FROM-clause entry for table "catalog_good"
HINT:  Perhaps you meant to reference the table alias "v0".

我想知道是否有机会通过Django进行CASE-WHEN-SELECT。 这是我想通过Django类改进的代码的一部分：

CASE
    WHEN (
        SELECT (score - "catalog_tag"."weight") ^ 2
        FROM "catalog_tag"
        WHERE "catalog_tag"."word" = 'chair' AND "catalog_tag"."good_id" = "catalog_good"."id"
    ) IS NOT NULL THEN (
        SELECT (score - "catalog_tag"."weight") ^ 2
        FROM "catalog_tag"
        WHERE "catalog_tag"."word" = 'chair' AND "catalog_tag"."good_id" = "catalog_good"."id"
    )
    ELSE (score ^ 2)
END

谢谢。