Laravel Query Item from table with selected relationships from another table - laravel

Question

There are two tables which are related - Product and SalesForecast. I want to query products of a certain supplier with sales forecast from a period.
Relationships are established. My query is as follows:
$products = Product::where('supplier_id', $supplier)
->whereHas('stock_forecasts_fk', function ($query) use ($begin, $end) {
$query->whereDate('date', '>', $begin);
$query->whereDate('date', '<', $end);
})
->get();
The relationship in the product model is as follows:
public function stock_forecasts_fk()
{
return $this->hasMany('App\Models\StockForecast');
}
This query does not work 100%. I want all products of that supplier to come (whether they have forecast or not). If they have a forecast, I need forecasts for that period only. Otherwise, that product will have not, forecast. But All product needs to come. Can someone advise how to fix this query so the result is as follows:
All products of suppliers come with relevant forecasts of between begin and end dates. If there is no forecast, then the product can come with no forecast.

Answer 1

You have to query with eager loading the relationship. with whereHas, only matching related value products will be collected. use with closure to query in related table
$products = Product::with(['stock_forecasts_fk' => function($query) {
$query->whereDate('date', '>', $begin)
->whereDate('date', '<', $end);
}])
->where('supplier_id', $supplier)
->get();

Answer 2

You can use with and pass a closure with your conditions to it:
$products = Product::where('supplier_id', $supplier)
->with(['stock_forecasts_fk' => function ($query) use ($begin, $end) {
$query->whereDate('date', '>', $begin)
->whereDate('date', '<', $end);
}])
->get();
From the docs:
Constraining Eager Loads
Sometimes you may wish to eager load a relationship, but also specify
additional query conditions for the eager loading query. Here's an
example:
$users = App\Models\User::with(['posts' => function ($query) {
$query->where('title', 'like', '%first%');
}])->get();
In this example, Eloquent will only eager load posts where the post's
title column contains the word first.

Answer 3

From the document that I've read here.
whereHas only includes Product which has stock_forecasts_fk, and discards Product which doesn't.
To select all product regardless it has stock_forecasts_fk, you should've use with.
$products = Product::where('supplier_id', $supplier)
->with([
'stock_forecasts_fk' => function ($query) use ($begin, $end) {
$query->whereDate('date', '>', $begin);
$query->whereDate('date', '<', $end);
}
])
->get();