Laravel eloquent how to get the minimum value that is not NULL?

This is the code in my Product model to get the minimum price value (one product can have multiple price)

public function getLowestAttribute ()
{
    return $this->prices->min('price');
}

But it will return NULL rather than the smallest integer if there is a NULL.

Basically I want to achieve this:

[1, NULL, 2] returns 1

[1, NULL, 0] returns 0

Any suggestion would be appreciated.

Answer

I found filter, and it works now.

public function getLowestAttribute ()
{
    $prices = $this->prices->filter(function ($item) {
        return !is_null($item->price);
    });

    return $prices->min('price');
}