我试图在2个不同的表中乘以列，并直接在laravel中的where语句中使用结果

My amount $amount = auth()->user()->cooperative->amount->where('year', Date('y'))->first()->amount;, and then i'm trying to multiply it with shares from contributions and compare product with actual amount in contributions$contributions = auth()->user()->cooperative->contributions->where("amount", "<", '($amount * share)');