Laravel如何在构建查询时访问关系？

Let's say I have tables

companies id | name
guests id | name
books id | name

They have models with relations
Company -> hasMany -> Guest
Guest -> hasMany -> Book

Now, I wanna get all books where guests from particular company
I have no Idea how to reach that in eloquent ORM
I will apreciate any help
Thanks

You can use whereHas to query based on the existence of relationships:

$books = Book::whereHas('guest.company', function ($query) use ($companyId) {
    $query->where('id', $companyId);
})->get();

Roughly: get all books that belong to a guest that belongs to a company with id of $companyId

$company = Company::with("guests.books")->find($id); // or how you get the company doesn't matter

$company->guests->books // gives you what you're looking for.

Note that, with("guests.books")is not necessary but, it provides you all data in single query

For more further you may want to check out official docs about relationships