How to achieve this complex query with Eloquent? - laravel

Question

I have this query below to get the email of all users that have a registration in a specific conference.
$users = User::whereHas('registrations', function ($query) use($conferenceID) {
$query->where('conference_id', '=', $$conferenceID);
})->get();
And dd($users) shows array:2 [▼ 0 => "....mail.com" 1 => "....mail.com"]. So its working fine.
But I want to get only the emails of the users that did a registration in a specific conference ($conferenceID) and this registration has 1 or more participants associated with a specific registration type.
Do you know how to properly achieve this query? I have the code below but it shows "Call to undefined relationship [Registration] on model [App\Conference]".
$getEmailsOfAspecificRegistrationType =
Conference::with('registrations',
'Registration.registrationTypes', 'Registration.registrationTypes.participants')
->where('id', $id)->get();
Table structure and example to explain better the context:
For example there is a conference "Conference 1" that has two registration types (rt1 and rt2). And for now there are only two registrations in the conference "Conference 1". One registration was done by Jake and other by Ben. Jake did a registration with 3 participants (him, Jane and Paul). Ben only did a registration for him. The tables structure is like below.
I want to get only the emails of the users that did a registration in the conference with id "1" and this registration has 1 or more participants associated with a specific registration type, for example "rt01". So in this case I only want to get the email of the user 1 "jakeemailtest" because is the only participant that did a registration that is associated with the registration type "rt01" because the participants Jake and Jane are associated with this registration type (as is possible to check in the participants table).
Conferentes table:
id name
1 Conference 1
Users table:
id name email
1 Jake jakeemailtest#test...
2 Ben benmailtest#test...
registration types table:
id name conference_id
1 rt1 1
2 rt2 1
Participants table:
id registration_id registration_type_id name
1 1 1 Jake
2 1 1 Jane
3 1 2 Paul
4 2 2 Ben
And the registrations table:
id status user_that_did_registration conference_id
1 Incomplete 1 1
2 Incomplete 2 1
Relevant models for the question:
Users model:
public function registrations(){
return $this->hasMany('App\Registration','user_that_did_registration');
}
Registration model:
// user that did the registration
public function customer(){
return $this->belongsTo(User::class, 'user_that_did_registration', 'id');
}
public function participants(){
return $this->hasMany('App\Participant');
}
public function conference(){
return $this->belongsTo('App\Conference');
}
Conference Model:
public function registrations(){
return $this->hasMany('App\Registration', 'conference_id');
}
Participants mode:
public function registration(){
return $this->belongsTo('App\Registration');
}
public function registration_type(){
return $this->belongsTo('App\RegistrationType');
}

Answer 1

According to your schema it looks like your model definitions should look like
User has Registrations => Registration belongs to User
Registration has Participants => Participant belongs to Registration
Registration Type has Participants => Participant belongs to Registration Type
Conference Has Registration Types => Registration Type belongs to Conference
Conference Has Registrations => Registration belongs to Conference
Considering above your Conference model should also have following mapping
public function registration_types(){
return $this->hasMany('App\RegistrationType', 'conference_id');
}
You could go with following to get the desired users
$users = User::whereHas('registrations.participants.registration_type', function ($query) use ($conference_id, $request) {
$query->where('name', '=', $request->rype)
->where('conference_id', '=', $conference_id);
})->whereHas('registrations', function ($query) use ($conference_id) {
$query->where('conference_id', '=', $conference_id);
})->get(); // use pluck('email') instead of get to select only email

Answer 2

You are specifying wrong relationship names. Strings that you provide in with() method should match the relationship methods name on model. The correct way to eager load relationships is:
$getEmailsOfAspecificRegistrationType = Conference::with(
'registrations.participants'
) ->where('id', $id)->get();
Also note that, you dont need to load each relation explicitly. When you eager load nested relationships, higher order relations are automatically loaded.