如何连接多个桌子导轨

Question

I've got a bit of code that I'm looking at the moment :

User.includes([:profile => :schedule]).where('...')

This loads all profiles and their schedules. So the query produced by this is select * user fields, select * profile fields, select * schedule fields

I'm filtering out users based on one field from profile and based on one field from profiles schedule but this above statement is selecting all the fields from all of these.

So I tried to do it with joins :

User.joins(:profile).joins('profiles.schedule').where('....').select('....')

This is throwing out error. I'm a former Java developer, still learning the rails stuff.

Answer 1

这应该工作：

User.joins(profile: :schedule).where('....').select('....')

Answer 2

Try this:

User.joins(profile: [:schedule]).where('...')

or

User.joins(profile: :schedule).where('...')

Answer 3

如果您已将您的Profile模型设置为通过has_many通过关联来进行关联Schedule ，则可以使用以下代码：

User.joins(:schedule).where('...')