Querying Relationship Existence, how to add conditions depending on an array length

问题

I would like to filter an item (pubs, in this case) by some characteristics that are stored in a separate table (tapps, in this case), and both are related by pub_tapps.

I have the following tables: pubs, tapps, pub_tapps(pub_id, tapp_id)

The relation between Pub and Tapp is the following:

 public function pubTapps()
{
    return $this->belongsToMany(Tapp::class, 'pub_tapps');
}

in my Pub model I tried the following testing for an array $request=[5,8, 7]:

public function pubsFilteredByTapps(FilteredTappsPubsRequest $request)
{
    $tapps_chosen = $request->get('tapps');

    $tapps_chosen = is_string($tapps_chosen) ? explode(',', str_replace('"', '', $tapps_chosen)) : $tapps_chosen;

    return Pub::whereHas('pubTapps', function($query) use($tapps_chosen) {
        $query->where('tapp_id', $tapps_chosen[0]);
    })
        ->whereHas('pubTapps', function($query) use($tapps_chosen) {
            $query->where('tapp_id', $tapps_chosen[1]);
        })
        ->whereHas('pubTapps', function($query) use($tapps_chosen) {
            $query->where('tapp_id', $tapps_chosen[2]);
        })
        ->get();
}

This is working perfectly, but for a given 3 dimensional array...

How can I do for an array of an n length??

I tried this, but doesn't work at all (returns an empty array):

return $pubs = Pub::whereHas('pubTapps', function ($query) use 
     ($tapps_chosen) {

        foreach ($tapps_chosen as $tappId) {
            $query->where('tapp_id', $tappId);
      }
       })->get();

What would I have to do??? Any ideas to make it work??

Thanks a lot!

回答1:

Use this:

$query = Pub::query();
foreach ($tapps_chosen as $tappId) {
    $query->whereHas('pubTapps', function($query) use($tappId) {
        $query->where('tapp_id', $tappId);
    });
}
return $query->get();

回答2:

How about this?

public function pubsFilteredByTapps(FilteredTappsPubsRequest $request)
{
    $tapps_chosen = $request->get('tapps');

    $tapps_chosen = is_string($tapps_chosen) ? explode(',', str_replace('"', '', $tapps_chosen)) : $tapps_chosen;

    return Pub::whereHas('pubTapps', function($query) use($tapps_chosen) {
        $query->whereIn('tapp_id', explode(',' $tapps_chosen));
    })->get();
}

This way if you have any number of IDs in the array, eloquent will generate a request with IN clause and you will get a proper result.

来源：https://stackoverflow.com/questions/50333566/querying-relationship-existence-how-to-add-conditions-depending-on-an-array-len