Laravel query using whereHas

Question

I have 2 models: car painted color, and cars

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

I need to search the latest painted car color but with whereHas, it's searching all colors

$colors = ['black', 'white'];
$cars->whereHas('color', function($cars) use ($colors) {
          return $cars->whereIn('paint_color', $colors);
});

How can I make whereIn to only query on the latest row?

Answer 1

First of all, since each car could have been painted many colors but you want to retrieve the latest painted color. This means you have a one to many relationship from car to color. Therefore the relationship color should be changed to

public function colors()
{
    return $this->hasMany(Colors::class)
        ->latest();
}

Then to only retrieve the latest color you can call ->limit(1) since the colors are already ordered by the relationship.

$cars = $query->with(['colors', function($query) {
        return $query->limit(1);
    }])
    ->get();

Then you can filter whether the latest color is in your $colors array

$filteredCars = $cars->filter(function($car) {
    return $car->colors->whereIn('paint_color', $colors);
});