默认是按照_Sortkey列或者_Identify列排序的,你试试改成这样
Select [_Identify], rownum as [_Sortkey], 编号, 数量 From (Selec t Row_Number() Over(Order by [_Identify] DESC) As RowNum, * from 订单) As a Where RowNum >= 1 And RowNum <= 50