MySQL--根據審覈時間排序，查詢最後一次審覈的物品採購記錄

select *
  from (select a.CheckDate, b.ProductID, b.Count, b.Price
          from tpurchase a, tpurchasedetail b
         where a.`Status` in (3, 4)
           and a.CheckDate is not null
           and a.PurchaseID = b.PurchaseID
         order by b.ProductID, a.CheckDate2 desc) m
 where (select count(1)
          from (select a.CheckDate, b.ProductID, b.Count, b.Price
                  from tpurchase a, tpurchasedetail b
                 where a.`Status` in (3, 4)
                   and a.CheckDate is not null
                   and a.PurchaseID = b.PurchaseID
                 order by b.ProductID, a.CheckDate2 desc) s
         where m.ProductID = s.productid and m.CheckDate > s.CheckDate) < 1