如何将范围与子查询或 find_by_sql 链接或组合
我想执行一个查询,
SELECT * FROM ( SELECT * FROM products ORDER BY price ASC ) AS s GROUP BY item;
该查询返回每件商品的所有产品中最便宜的。使用此子查询很好,因为它可以在 O(N logN) 时间内运行。
因此,我可以使用 find_by_sql 找到它,但如果能够将它与 Product 的其他作用域链接起来,那就太好了。
有人知道如何将其写为作用域或链作用域和 find_by_sql 吗?
I would like to perform a query like
SELECT * FROM ( SELECT * FROM products ORDER BY price ASC ) AS s GROUP BY item;
which return the cheapest of all products for each item. Using this subquery is good because it can run in O(N logN) time.
So I can find this with find_by_sql, but it would be nice to be able to chain it with other scopes for Product.
Anyone know how to either write this as a scope or chain scoped and find_by_sql?
你应该能够做类似的事情
You should be able to do something like