ruby-on-rails - Activerecord rails 中的子查询

Question

我有一个这样的复杂查询：

SELECT count(*)
FROM users a 
WHERE source = 1 
  AND ... -- COMPLEX QUERY
  AND NOT EXISTS (
    SELECT 1 FROM users b
    WHERE b.source = 0
      AND ... -- COMPLEX QUERY
      AND b.key = a.key
);

COMPLEX QUERY生成于：

Rails:
@scope = User.complex_scope(params)

如何在 Rails 中通过 Activerecord 构建上述查询？

谢谢！

标签： ruby-on-rails