Laravel hasManyThrough interrogate the intermediate relationship as well as distant - php

Question

I want to perform the following (with some rather crude pseudo code):
SELECT a users orderLines WHERE the orderheader's status ='paid' AND the orderLine's productId>5
In other words, a user can place many orders. Each order has one or many order lines. I want to find all of the order lines that the user has placed (order lines, not orders) but only if the order header has a certain status, and only if the order line has another parameter checked. This could be the date the line was added, or the productId being x, and so on.
Simple enough to do with a standard MySql query.
I have the nescessary models:
User
OrderHeader (Intermediate relationship)
OrderLine (Distant relationship - this is what I want to fetch, via the intermediate)
Here are how the relationships are defined in each model:
User
public function orders()
{
return $this->hasMany('App\OrderHeader', 'user_id', 'id');
}
public function lines()
{
return $this->hasManyThrough('\App\OrderLine', 'App\OrderHeader', 'user_id', 'order_header_id');
}
OrderHeader
public function lines()
{
return $this->hasMany('App\OrderLine', 'order_header_id', 'id');
}
public function user(){
return $this->belongsTo('User', 'id', 'user_id');
}
OrderLine (Fetch these for the User, using hasManyThrough)
public function header()
{
return $this->belongsTo('App\OrderHeader', 'order_header_id');
}
public function products()
{
return $this->belongsToMany('App\Product');
}
So, I load the User, using:
$person = User::findOrFail($id)
Then I can use:
$user->lines()->where('product_id','>=',10)->paginate(20);
So, that works brilliantly to get ALL of the lines that the user has placed, which match the condition on the line records. However, I can't figure out how to add a second condition on the intermediate, so that not only do I check the product_id, but also interrogate the OrderHeader entity via the orders() relationship.
I've tried:
return $user->orders()->where('status','=','Paid')->lines()->where('product_id','>=',20))->paginate(20);
but that returns the error: Call to undefined method Illuminate\Database\Query\Builder::lines()

Answer 1

hasManyThrough is a special case in Eloquent, where table is joined (intermediate table), so it's pretty simple - just query that table. Nothing to do with the other relation.
This is what you want:
$throughTable = $user->lines()->getParent()->getTable();
$user->lines()
->where('product_id', '>=', 10)
->where('orderheaders.status', 'paid')
// or
// where("{$throughTable}.status', 'paid')
->paginate(20);
Btw this relation is wrong:
// OrderHeader model
public function user(){
return $this->belongsTo('User', 'id', 'user_id'); // wrong keys order
}
// should be
public function user(){
return $this->belongsTo('User', 'user_id', 'id');
}