Best way to query model relationship in Eloquent - laravel

Question

I am working within a controller in a Laravel application. I am returning a table to the view. The table is based on my PlanSubmission model. I am receiving parameters through a GET request and using those parameters to return a filtered set of rows to my view.
The first part of my controller looks like this and is working fine:
public function index()
{
//Used for filter. The request is received in the URL
if (request()->has('status')) {
$plans = PlanSubmission::where('status', request('status'))->paginate(25)->appends('status', request('status'));
}
elseif (request('employer_name')) {
$plans = PlanSubmission::where('employer_name', request('employer_name'))->paginate(25)->appends('employer_name', request('employer_name'));
}
I have run into a problem because now I need to use a model relationship in the controller. I am receiving 'advisor_name' from the request. The 'advisor_id" column is the foreign key on the PlanSubmission model. The 'advisor_name' column exists in the Advisor model. I have a function on my PlanSubmission model that looks like this:
public function advisor()
{
return $this->belongsTo(Advisor::class);
}
Initially, I thought there was a way I could do this easily with something like:
$plans = PlanSubmission::where(advisor->name, request('advisor_name'))->paginate(25)->appends('advisor_name', request('advisor_name'));
Of course, this will not work because I cannot enter a relationship into the first parameter in the Where Clause.
I do not know where to go from here. My other thought is to return all the advisors first from the Advisor model like this:
$advisors = Advisor::where('name', request('advisor_name'));
Then, I imagine I would have to somehow loop through that and get the id (primary key) for each of the objects in $advisors and somehow get that into the PlanSubmission where clause. I'm totally lost.

Answer 1

Like Victor mentions in his answer you can use whereHas like so:
PlanSubmission::whereHas('advisor', function ($query) {
$query->where('name', request('advisor_name'));
});
You didn't asked this directly, but I noticed that you use conditionals to make different queries. Eloquent provides a few way to make this a bit nicer to deal with.
The first which is kind of obvious is that that whatever method you call a builder (query) is returned that you can just add on to. It could be there were some common restrictions in your two cases:
public function index()
{
$query = PlanSubmission::where('something', 42);
if (request()->has('status')) {
$query = $query->where('status', request('status'));
} elseif (..) {
...
}
return $query->paginate(25);
}
Another way to do conditional queries in Laravel is using when. E.g. for status:
$query = $query->when(request->has('status'), function ($query) {
// note that you don't have to return the query
$query->where('status', request('status'));
});
// or PlanSubmission::>when(..)
In your example you cannot both filter by status AND advisor_name, but lets assume that would be okay, then you can combine everything like so:
public function index()
{
return PlanSubmission::query()
//->where('something', 42)
->when(request->has('status'), function ($query) {
$query->where('status', request('status'));
})
->when(request->has('advisor_name'), function ($query) {
$query->whereHas('advisor', function ($query) {
$query->where('name', request('advisor_name'));
});
})->paginate(25);
}
This approach may seem verbose for simple queries and then it is fine to use if conditions, but for complex queries when can be useful. Also the idea of "building up a query" also works nice in those situation. You can pass the query builder around and continuously build it up.

Answer 2

You can use whereHas for that
docs