rails 奇怪的 joins

最新推荐文章于 2018-12-20 10:30:23 发布

转载最新推荐文章于 2018-12-20 10:30:23 发布 · 140 阅读

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原文链接：https://my.oschina.net/kelby/blog/194189

本文深入探讨了Rails中关联查询的方法，特别是如何使用joins进行复杂条件的指定，并提供了实际的例子来展示如何查找昨天创建的订单。

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rails 奇怪的 joins

@wish_products = WishProduct.joins(:product).where("product_id = products.id AND customer_id = ?",current_customer.id).order('created_at DESC')

注意这里的 joins(:products) 还有以后的 products.id (复数！)

12.3 Specifying Conditions on the Joined Tables You can specify conditions on the joined tables using the regular Array and String conditions. Hash conditions provides a special syntax for specifying conditions for the joined tables:

time_range = (Time.now.midnight - 1.day)..Time.now.midnight Client.joins(:orders).where('orders.created_at' => time_range) An alternative and cleaner syntax is to nest the hash conditions:

time_range = (Time.now.midnight - 1.day)..Time.now.midnight Client.joins(:orders).where(orders: {created_at: time_range}) This will find all clients who have orders that were created yesterday, again using a BETWEEN SQL expression.

http://guides.rubyonrails.org/active_record_querying.html#specifying-conditions-on-the-joined-tables

转载于:https://my.oschina.net/kelby/blog/194189