Laravel Eloquent，只选择关系存在的行

Question

I am trying to select from a table, but I only want to select things that have an existing relationship.

For example, if I have Users and Comments, and Users haveMany Comments, I want to do something like:

User::hasComments()->paginate(20);

So, I only want to select Users that have at least 1 Comment, and paginate the result of that query. Is there any way to do this?

Answer 1

根据Laravel查询关系的Eloquent 文档（查找“查询关系存在”子标题），这应该有效：

User::has('comments')->paginate(20);

Answer 2

Flip your thinking upside down and I think that you can do it.

$userIds = Comment::distinct()->select('user_id')->groupBy('user_id')->get();

You may not need the groupBy() but that should get you started towards a way to do it.

Then you should be able to iterate through each like so:

foreach($userIds as $id) {
    $user = $id->user;  //$id is technically a Comment instance so you can
                        //  call the methods on that model
    echo $user->name;
}

Answer 3

Simply like this:

User::has('comments')->with('comments')->get();