I have three models that Im working with here: User, Deal, and Investment.
我有三种模特在这里工作：用户，交易和投资。
User has many deals User has many investments
用户有很多交易用户有很多投资
Deal belongs to user Deal has many investments
交易属于用户交易有很多投资
Investment belong to deal Investment belong to user
投资属于交易投资属于用户
I want to find all investments from a user where the deal.deal_type_id = 3 for that investment.
我想查找来自用户的所有投资，其中deal.deal_type_id = 3用于该投资。
3 个解决方案
#1
2
If you have setup your associations, its pretty simple.
如果您已经设置了关联，那很简单。
# user.id = 1
User.find(1).deals.where(:deal_type_id => 3)
#2
1
If you use the squeel gem, then it's quite a bit more intuitive.
如果你使用squeel gem，那么它会更加直观。
Assuming you've already retrieved the user you want to find investments for:
假设您已经检索了要查找投资的用户：
user.investments.joins{ deals }.where { deal.deal_type_id == 3 }
#3
0
Like @Stephen said but for Active Record:
就像@Stephen说的那样但是对于Active Record：
type = 3
user.investments.joins('deals').where('deals.deal_type_id == ?', type)
#1
2
If you have setup your associations, its pretty simple.
如果您已经设置了关联，那很简单。
# user.id = 1
User.find(1).deals.where(:deal_type_id => 3)
#2
1
If you use the squeel gem, then it's quite a bit more intuitive.
如果你使用squeel gem，那么它会更加直观。
Assuming you've already retrieved the user you want to find investments for:
假设您已经检索了要查找投资的用户：
user.investments.joins{ deals }.where { deal.deal_type_id == 3 }
#3
0
Like @Stephen said but for Active Record:
就像@Stephen说的那样但是对于Active Record：
type = 3
user.investments.joins('deals').where('deals.deal_type_id == ?', type)