Rails 使用散列数组查找记录

问题描述

(使用 in 子句按字段对选择查询)

(Select Query by Pair of fields using an in clause)

我有一个看起来像这样的哈希数组:

I have an array of hashes that looks like this:

[ {product_id: 7629, group_id: 4}, {product_id: 8202, group_id: 3} ]

我想返回的是 Items 表中匹配数组中字段对的所有记录.

What I would like to return are all the records in the Items table that match the pair of fields in the array.

在 SQL 中，它会像这样检索:

In SQL it would be retrieved like this:

SELECT *
FROM items
WHERE (product_id, group_id) IN (VALUES (7629,4), (8202,3))

但是我在使用 rails .where 子句时遇到了麻烦.这甚至可能吗?

But I am having trouble doing this with a rails .where clause. Is this even possible?

推荐答案

我认为在这种情况下使用 SQL 的 IN 没有任何好处.

I see no benefit in using SQL's IN in this case.

我会使用 where 作为第一个条件，并使用 or(并让 Rails 负责消毒和繁重的工作):

I would use where for the first condition and chain all other conditions with or (and let Rails take care of sanitizing and heavy lifting):

array = [{ product_id: 7629, group_id: 4 }, { product_id: 8202, group_id: 3 }]
array[1..-1].inject(Model.where(array[0])) { |m, h| m.or(Model.where(h)) }

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