Laravel Eloquent hasMany filtered by parent table

Question

In my system there are users, each of which has holiday allowances each year.

There are 3 tables (simplified):

users
- id
- name

user_leave_allowances
- id
- user_id
- from
- to
- allowance

user_leave
- id
- user_id
- from
- to
- days

In the UserLeaveAllowance model I have set up the following relationship:

public function leave(){
    return $this->hasMany('App\UserLeave','user_id','user_id');
}

And retrieving the leave allowance by the following:

$leaveAllowance = UserLeaveAllowance::with(['leave'])
->where('user_id',$id)
->get()

This pulls in the full list of leave allowances (user_leave_allowances) for that user along with all the leave they have currently requested (user_leave).

However, the allowances will be for different periods of time, eg 1/1/2017 - 31/12/2017 and leave will be taken out of these periods. So for each leave allowance period I want just the leave that falls within those two dates (from & to), at the moment it just pulls through all the leave for that user into each leave allowance.

I have tried many different ways around it, using the where conditions on the hasMany as such...

public function used(){
    return $this->hasMany('App\UserLeave','user_id','user_id')
->where('from', '>=', 'user_leave_allowances.from')
->where('to', '<=', 'user_leave_allowances.to');
}

and

public function used(){
    return $this->hasMany('App\UserLeave','user_id','user_id')
->whereRaw('user_leave.from >= user_leave_allowances.from')
->whereRaw('user_leave.to <= user_leave_allowances.to');
}

But I just can't figure out a way to get this to work. I'm fairly new to Laravel and trying to get to grips with Eloqent and relationships, I'm sure the answer isn't too far away.

Answer 1

Here's my suggestion:

users - id - name

user_leave_allowances - id - user_id - from - to

user_leave - id - user_leave_allowances_id - from - to

In short relate your leave with your leave allowances rather than the user directly because in essence a leave request is taken out of the allowance not out of the user directly.

class User extends Model {
     public leaveAllowance() {
         return $this->hasMany(UserLeaveAllowance::class);      
     }        
} 

class UserLeaveAllowance {
      public user() { return $this->belongsTo(User::class); }
      public leaveRequests() { 
        return $this->hasMany(UserLeave::class);
      }
}

class UserLeave {
      public allowancePeriod() { 
        return $this->belongsTo(UserLeaveAllowance::class);
      }
} 

Now you can do things like:

UserLeaveAllowance::whereHas("user", function ($q) { 
        return $q->where("id", <user id>); //Allowances for this user
})->leaveRequests() 
->selectRaw("SUM(TIMESTAMPDIFF(DAY, to, from)) as days")
->value("days");