为Laravel添加条件有（）

Question

I have a table named answers and its columns are id, answers, batch, candidate_id. I want to get all candidates that has no record of answers under batch number of 1.

Is there a way to add condition to this statement (this is in my candidate model) ?

return $this->has('answers', '=', 0)->get();

I tried this way but it didn't work:

return $this->has('answers', '=', 0)->whereBatch(1)->get();

Answer 1

You need whereHas:

$this->whereHas('answers', function ($q) {
   $q->whereBatch(1);
}, '=', 0)->get();

Btw this is exactly the same as calling has with closure as 5th param:

$this->has('answers', '=', 0, 'and', function ($q) {
   $q->whereBatch(1);
})->get();