Laravel join same table for 2 columns - php

Question

I do currently have this code:
return Datatable::query($query = DB::table('acquisitions')
->where('acquisitions.deleted_at', '=', null)
->where('acquisitions.status', '!=', 2)
->join('contacts', 'acquisitions.contact_id', '=', 'contacts.id')
->join('user', 'acquisitions.user_id', '=', 'user.id')
->select('contacts.*', 'acquisitions.*', 'acquisitions.id as acquisitions_id', 'user.first_name as supervisor_first_name', 'user.last_name as supervisor_last_name', 'user.id as user_id'))
The data from the user table is used for 2 columns: acquisitions.supervisor_id and acquisitions.user_id. I need the first_name and the last_name for both of this tables, the above query does however currently only use the id from the acquisitions.user_id field. I also tried to use a table alias, that does also not work, I assume that I'm doing something wrong here.
So in short: I also need that the query selects the data for the user, based on the id from the acquisitions.supervisor_id and makes it available as supervisor_first_name and supervisor_last_name.

Answer 1

According to your next to last comment on the other answer, you need a self join per reference table. Try this:
$result = DB::select('SELECT
u.name user_first_name,
u.last_name user_last_name,
u.email user_email,
s.name supervisor_name,
s.last_name supervisor_last_name,
s.email supervisor_email
FROM acquisitions a
JOIN users u ON a.user_id = u.id
JOIN users s ON a.supervisor_id = s.id');
return $result;
Note that $result is an array of StdClass objects, not a Collection, but you can still iterate it and call the current item's values:
foreach ($result as $item) {
print($item->supervisor_first_name);
}
If you need a WHERE clause, e.g. to get a specific user's row from acquisitions, you would do that by adding a parameter to the query like so:
$result = DB::select('SELECT
u.name user_first_name,
u.last_name user_last_name,
u.email user_email,
s.name supervisor_name,
s.last_name supervisor_last_name,
s.email supervisor_email
FROM acquisitions a
JOIN users u ON a.user_id = u.id
JOIN users s ON a.supervisor_id = s.id
WHERE a.user_id = ?
', [3]);
EDIT
If you need the resultset to be a Collection, you can easily convert the array to one, using the hydrate method:
$userdata = \App\User::hydrate($result); // $userdata is now a collection of models

Answer 2

It should be something like;
return Datatable::query($query = DB::table('acquisitions')
->where('acquisitions.deleted_at', '=', null)
->where('acquisitions.status', '!=', 2)
->join('contacts', 'acquisitions.contact_id', '=', 'contacts.id')
->join('user', 'acquisitions.user_id', '=', 'user.id')
->select( \DB::raw(" contacts.*, acquisitions.*, acquisitions.id as acquisitions_id, user.first_name as supervisor_first_name, user.last_name as supervisor_last_name, user.id as user_id ") )
);

Answer 3

$devices = DB::table('devices as d')
->leftJoin('users as au', 'd.assigned_user_id', '=', 'au.id')
->leftJoin('users as cu', 'd.completed_by_user_id', '=', 'cu.id')
->select('d.id','au.name as assigned_user_name','cu.name as completed_by_user_name');
Also follow this link
https://github.com/yajra/laravel-datatables/issues/161