Why ->latest method in model method read all rows from related table?

Question

In laravel 9 I got last value in related CurrencyHistory table

$currencies = Currency
    ::getByActive(true)
    ->withCount('currencyHistories')
    ->with('latestCurrencyHistory')
    ->orderBy('ordering', 'asc')
    ->get();

In model app/Models/Currency.php I have :

public function latestCurrencyHistory()
{
    return $this->hasOne('App\Models\CurrencyHistory')->latest();
}

But checking generated sql I see lines like :

   SELECT * 
    FROM `currency_histories` 
    WHERE `currency_histories`.`currency_id` in (8, 13, 16, 19, 27, 30) 
    ORDER BY `created_at` desc 

I suppose this code is raised by latestCurrencyHistory method and wonder can I set some limit 1 condition here, as resulting data are too big.

Thanks!

Answer 1

Query is correct. As you eager load your relation for the collection of currencies using with method, you load currency_histories for all of your Currency models in collection.

If you dump the result, you will have currencies with IDs: 8, 13, 16, 19, 27, 30 and one latestCurrencyHistory (if present) for each.