如何在rails3中将数据传递给IN查询-HowtopassdatatoINqueryinrails3

22  

You can just pass an array in. Rails is clever enough to to the right thing with it:

你可以直接传入一个数组.Rails很聪明，可以用它来做正确的事情：

items = [
  @invitation_user1.id,
  @invitation_user2.id,
  @user1.id,
  @user2.id,
  @profile1.id,
  @profile2.id
]

@activities = Version.where("item_id IN (?)", items)
# or equivalently:
@activities = Version.where(:item_id => items)

This is vastly preferred over your variant, as Rails properly handles escaping of all passed values for the used database adapter.

这比您的变体更受欢迎，因为Rails正确处理所使用的数据库适配器的所有传递值的转义。

1  

Use array instead of string.

使用数组而不是字符串。

For example

例如

ids = [ @invitation_user1.id, @invitation_user2.id, @user1.id, @user2.id ]

Then easily you can find the records by

然后很容易就可以找到记录了

@versiOns= Version.find_all_by_id(ids)

This will result the query you expected.

这将导致您期望的查询。

SELECT "versions".* FROM "versions" WHERE (item_id IN (19,20,4,1))

1  

What you are looking for is split:

您正在寻找的是分裂：

[1] pry(main)> a = '19,20,4,1,1,4,1'
=> "19,20,4,1,1,4,1"
[2] pry(main)> a.split(',')
=> ["19", "20", "4", "1", "1", "4", "1"]
[3] pry(main)> a.split(',').map(&:to_i)
=> [19, 20, 4, 1, 1, 4, 1]

But, as you are constructing the 'string' manually, better to use an array:

但是，当您手动构建“字符串”时，最好使用数组：

items = Array.new
items <<@invitation_user1.id <<@invitation_user2.id <<@user1.id
items <<@user2.id <<@user2.id <<@profile1.id <<@profile2.id
@activities = Version.where(item_id: items) 

Anyway, the way to get the ids is strange because... what would happen if you added more users? or profiles?

无论如何，获取ID的方式很奇怪，因为......如果添加更多用户会发生什么？或个人资料？

What I would do (seeing as little as we can see in your example)

我会做什么（在你的例子中我们看到的很少）

items = Array.new
items <

def get_invitation_user_ids
  InvitationUser.select(:id).map(&:id)
end

...