Laravel -多对多关系，按产品功能计算产品数量

Schema::create('products', function (Blueprint $table) {
    $table->id();
    $table->string('name');
    $table->timestamps();
});

Schema::create('features', function (Blueprint $table) {
    $table->id();
    $table->string('name');
    $table->timestamps();
});

Schema::create('product_feature', function (Blueprint $table) {
    $table->id();
    $table->unsignedBigInteger('product_id');
    $table->unsignedBigInteger('feature_id');
    $table->timestamps();

    $table->foreign('product_id')->references('id')->on('products')->onDelete('cascade');
    $table->foreign('feature_id')->references('id')->on('features')->onDelete('cascade');
});

class Product extends Model
{
    public function features()
    {
        return $this->belongsToMany(Feature::class);
    }
}

class Feature extends Model
{
    public function products()
    {
        return $this->belongsToMany(Product::class);
    }
}

// 获取具有特定功能的产品数量
$featureName = '无线充电';
$count = Product::whereHas('features', function ($query) use ($featureName) {
    $query->where('name', $featureName);
})->count();

echo "具有 '$featureName' 功能的产品数量: " . $count;