Eager Load Relation, When Relation Doesn't Exist - laravel

Question

So, I have a Product model which belongsTo('App\Tax'). A Product may or may not be associated with a Tax (the tax_id fk in Product could be null).
The query below works fine as long as I have at least one Product associated with a Tax:
\App\Product::with("tax")->get()
It starts throwing the following exception, when none of the Product's have associated Taxes:
Illuminate\Database\QueryException with message 'SQLSTATE[22P02]: Invalid text
representation: 7 ERROR: invalid input syntax for uuid: "0" (SQL: select *
from "taxes" where "taxes"."id" in (0))'
While this exception is quite understandable, my question is how do I avoid this situation?
Note: The tax.id column is of postgres uuid type.
EDIT 1
I should explicitly mention that I'm trying to write a query to fetch all Products, belonging to a particular Organization, whether they're associated with a Tax or not.
The query above, works just fine as long as there is at least one Product associated with a Tax. It throws QueryException if all the products (1 or more), are not associated with any tax.
EDIT 2
So, I got a working solution, that doesn't seem quite right. I'm still open to a better solution. Here's how I got it to work:
// First just fetch all the products using whatever criterion
$products = $query
->orderBy ($params["orderBy"], $params["sortDir"])
->skip ($params["start"])
->take ($params["length"])
->get();
// Then, load the relation, if there's at least one product having
// that relation.
// Solution requires one additional aggregate query per relation
// than a regular with() clause would have generated
$relations = array('purchase_tax', 'sale_tax', 'category');
foreach($relations as $relation) {
$count = $org->products()
->whereHas($relation, function($query){
$query->whereNotNull('id');
})
->count();
if ($count) {
$products->load($relation);
}
}
This gives me all products, even if none of them have the associated relations.

Answer 1

You can go many ways.
Use has \App\Product::has('tax')->whith('tax')->get(); It will get product that have at least one Tax
based on condition for relationship
\App\Product::whereHas('tax', function ($query) {
$query->where('content', 'like', 'foo%');
})->whith('tax')->get();
\App\Product::with(['tax' => function ($query) {
$query->whereNotNull('product_id');
}])->get(); With but subquery where product_id is not null;
$products = \App\Product::get();
if ($products->tax()->count() > 0) {
$products->load('tax');
}
Lazy Load Count the product tax and if greater then 0 lazy load them
Hope it helps!

Answer 2

I do not like to answer my own questions, but since I've not received any answers, I'm posting one myself, for the benefit of whomsoever it may concern.
I got a working solution, that doesn't seem quite right. I'm still open to a better solution. Here's how I got it to work:
// First just fetch all the products using whatever criterion
$products = $query
->orderBy ($params["orderBy"], $params["sortDir"])
->skip ($params["start"])
->take ($params["length"])
->get();
// Then, load the relation, if there's at least one product having
// that relation.
// Solution requires one additional aggregate query per relation
// than a regular with() clause would have generated
$relations = array('purchase_tax', 'sale_tax', 'category');
foreach($relations as $relation) {
$count = $org->products()
->whereHas($relation, function($query){
$query->whereNotNull('id');
})
->count();
if ($count) {
$products->load($relation);
}
}
This gives me all products, even if none of them have the associated relations.