Laravel Eloquent - 根据父表中列的值定义与三个可能表之一的关系

Let's say I have a blog post with a comment section. Using Laravel Eloquent I get data from the 'comments' table and the relational 'users' table. Something like this:

Comment::where('post_id', $post_id)
       ->with('user')
       ->get();

The 'users' table has a column called 'user_type' with the value 'user' or 'admin'.

If the user_type in the users table is user I want to get relational data from the regular_users table like this: ->with(user.regular_user).

If the user_type in the users table is admin I want to get relational data from the admins table like this: ->with('user.admin')

(All the relationships are defined properly in the models.)

How do I do this?

Instead of with, try the following with whereHas:

i.e.:

$regular_users = Comment::where('post_id', $post_id)
   ->whereHas('user',function ($user) {
       $user->where('user_type', 'user')->with('regular_user');
   })       
->get();