Laravel eloquent get the latest row of related table

Because relationships are separate queries, you can't add a limit to an eager loaded relationship. If you do, this limits the entire relationship query, it does not act as a limit per related object.

Luckily, your requirement can be implemented simply with an additional relationship:

public function latestChapter() {    return $this->hasOne(Chapter::class)->latest();}

Now, instead of eager loading the entire chapters relationship, you can just eager load your new latestChapter relationship.

$books = Book::with(['authors', 'categories', 'latestChapter'])->get();

I know it is an old post, but there are some new solutions and I want to share it with you.In laravel 8, there are new helper functions: latestOfMany , oldestOfMany and ofMany.For your example, you could use:

public function latestChapter() {    return $this->hasOne(Chapter::class)->latestOfMany();}

For those who are not able to upgrade laravel 8.4 to have ->latestOfMany method, hasOne relation can be enhanced with a self join to filter out latest related model per each main model

public function lastchapter(){    return $this->hasOne(Chapter::class)->join(DB::raw("(           SELECT MAX(id) as id, book_id           FROM `books` as `books_sub`           GROUP BY book_id        ) as lastchapters"), function ($join) {        $join->on("lastchapters.id", '=', "books.id");    })->whereRaw('lastchapters.id = books.id');}