Merge 'with' and 'whereHas' in Lar

问题:

I have this code in Laravel 5, using Eloquent, which is working perfectly:

$filterTask = function($query) use ($id) {
    $query->where('taskid', $id);
};

User::whereHas('submissions', $filterTask)->with(['submissions' => $filterTask])->get();

Basically the goal is to get only those users with their filtered submissions, which has any of them. However, it seems wasting to run both whereHas and with methods with the same callback function. Is there a way to simplify it?

Thanks.

回答1:

In terms of performance you can't really optimize anything here (except if you were to move from eloquent relations to joins). With or without whereHas, two queries will be run. One to select all users another one to load the related models. When you add the whereHas condition a subquery is added, but it's still two queries.

However, syntactically you could optimize this a bit by adding a query scope to your model (or even a base model if you want to use this more often):

public function scopeWithAndWhereHas($query, $relation, $constraint){
    return $query->whereHas($relation, $constraint)
                 ->with([$relation => $constraint]);
}

Usage:

User::withAndWhereHas('submissions', function($query) use ($id){
    $query->where('taskid', $id);
})->get();