主题：请教SQL语句

 sql语句你最后只需要得到一行数据？你的逻辑是不是有问题？

 Select top 1 b.[产品编码] from {编码表} As a Inner join {订单明细} As b on a.[MID] = b.[MID] And a.[CID] = b.[CID] where 条件 order by [_Identify] desc