Query an object via multiple pivot tables with Laravel's ORM Eloquent - php

Question

What I want to do, is to retrieve data through multiple relationships (pivot tables).
I have three database tables
users, cities, and jobs.
They are built like this (They aren't, just to give you a glimpse)
Users table
id int(11) PK, Autoincrement,
name varchar(255)
Cities table
id int(11) PK, Autoincrement,
name varchar(255)
Jobs table
id int(11) PK, Autoincrement,
name varchar(255)
Now I have pivot tables, because these are many to many relationships. I got the tables city_user and job_user.
CityUser table
city_id int(11),
user_id int(11)
JobUser table
job_id int(11),
user_id int(11)
In every Class (User, City, Job), I got the relationships defined with a belongsToMany method.
City class
/**
* Defines the relation between the city and its users
*
* #return \Illuminate\Database\Eloquent\Relations\BelongsToMany
*/
public function users()
{
return $this->belongsToMany(User::class, 'city_user');
}
User class
/**
* Defines the relation between the user and its cities
*
* #return \Illuminate\Database\Eloquent\Relations\BelongsToMany
*/
public function cities()
{
return $this->belongsToMany(City::class, 'city_user');
}
The same goes for the jobs table. What I now want to do is to get all users that are in a specific city and have a specific job.
Let's imagine I want to query all users who live in City with the ID 5, and have the job with the ID 10.
Going for one relationshiop is fairly easy
$users = City::find(5)->users;
or
$users = Job::find(10)->users;.
But, how do I achieve that for multiple relationships in this case? I tried to do it like this
$users = City::find(10)->with(['users' => function($query) use ($jobId) {
// Here I'm stuck. I wouldn't know how to query further? Maybe like this
return $query->with('jobs')->whereJobId($jobId);
}]);
But, when I do it like this, I'm getting 0 results, so there must be something wrong. Any ideas?
I'm getting an error though
Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42S22]: Column not found: 1054 Unknown column 'job_id' in 'where clause'' in
I also tried it like this (inside the with(['consultants']))
$query->with(['jobs' => function ($query) use ($jobId) {
$query->whereJobId($jobId);
}]);
but that doesn't look right. Also I'm getting a Collection of Cities, but I need one of Users.
Then I tired it (temporary) like this
$users = User::with(['cities' => function ($query) use($cityId) {
/** #var \Illuminate\Database\Eloquent\Relations\BelongsToMany $query */
$query->wherePivot('city_id', $cityId);
}])->get();
But, then I'm getting ALL users, instead of just the ones, which is even more confusing, because the documentation says
Sometimes you may wish to eager load a relationship, but also specify additional query constraints for the eager loading query. Here's an example:
$users = App\User::with(['posts' => function ($query) {
$query->where('title', 'like', '%first%');
}])->get();
In this example, Eloquent will only eager load posts that if the post's title column contains the word first. Of course, you may call other query builder to further customize the eager loading operation:
But why doesn't it work then?

Answer 1

You can solve your fatal error this way:
$users = City::find(10)->with(['users.jobs', function($query) use ($jobId) {
$query->whereJobId($jobId);
});
}]);
But this will not filter the users for a specific job ID. For example we have two users with IDs 1 and #2. User 1 is related to job 10 while user 2 is not. The code above will give you both users for $jobId = 10, because the users query will be executed first without any filters for jobs and the jobs query will be executed after the users query.
You have to use the join() method of the query builder:
$users = User::join('job_user', 'users.id', '=', 'job_user.user_id')
->join('city_user', 'users.id', '=', 'city_user.user_id')
->where('job_user.job_id', $jobId)
->where('city_user.city_id', $cityId)
->get();