Laravel, find ids using query where those ids are in another table - php

Question

I have two tables, school_users and users. I need to create a query, using Eloquent, that gets all users where user_id equal school_id.
so the result must be more than one user, so that also I need to group the result by school_id
thank you in davance
Relations:
User Model:
public function school()
{
return $this->hasMany(SchoolUser::class);
}
SchoolUser Model:
public function user()
{
return $this->hasMany(User::class);
}
School_users table:
+----+---------+------------+-------------+
| id | user_id | school_id | created_at |
+----+---------+------------+-------------+
| 1 | 79 | 79 | <SOME TIME> |
| 2 | 85 | 79 | <SOME TIME> |
| 3 | 86 | 85 | <SOME TIME> |
| 4 | 87 | 85 | <SOME TIME> |
+----+---------+------------+-------------+
users table:
+----+
| id |
+----+-
| 79 |
| 85 |
| 86 |
| 87 |
+----+-
User Model:
public function getUsers()
{
return $this
->leftJoin('school_users', $this->table . '.id', '=', 'school_users.school_id')
->select(
$this->table . '.*',
'school_users.school_id as school_id'
)
->whereIn('users.id', '=', 'school_users.school_id')
->orderBy('id', 'desc')
->get();
}

Answer 1

Use whereColumn to filter user_id equal to school_id,
and use join instead of leftjoin:
public function getUsers()
{
return $this
->join('school_users', function($join) {
$join->on('school_users.user_id', '=', $this->table.'.id')
->whereColumn('school_users.user_id', 'school_users.school_id');
})
->select
(
$this->table.'.*',
'school_users.school_id as school_id'
)
->orderBy($this->table.'.id','desc')
->get();
}