我有一些查询问题。我需要从该查询中获取最大值和product_name：

select
    products.product_name,
    sum(product_invoice.product_amount) as total_amount
from 
    product_invoice
inner join 
    products on product_invoice.product_id = products.product_id
inner join 
    invoices on product_invoice.invoice_id = invoices.invoice_id
where 
    month(invoices.invoice_date) = 2
group by 
    products.product_name

该查询返回如下结果：

product_name  | total_amount
--------------+--------------
      chairs  |  70              
      ladders | 500  
      tables  | 150  

如何从中得到：ladders 500？