SQL 服务器 - 我将如何对上个月的产品进行排名？

Question

我已经开始充实一些内容，但是我在添加某种 window 函数以获得在我的代码中调用数据、产品的预期结果时遇到了问题按上月销售额排名。如果可以提供任何帮助，我将不胜感激！

这是被问到的问题：

The CEO would like to know the sales based on last month's sales. Please provide her with a query to rank the products by the number of orders in the last month. There should be NO SKIPPED NUMBERS.

这是我目前得到的：

SELECT 
    P.NAME AS 'Product Name',
    Isnull(Count(DISTINCT O.OrderID), 0) AS 'Orders Count',
    Sum(Isnull(o.ordertotal, 0)) AS 'Orders Total',
    Sum (Isnull(oi.orderitemquantity, 0)) AS 'Item Total'
 FROM 
    Product P
 INNER JOIN 
    OrderItem OI ON OI.ProductID = P.ProductID
 INNER JOIN 
    Orders O ON O.OrderID = OI.OrderID
GROUP BY 
    P.Name

这也需要在存储过程中，因此任何帮助也将非常有用。

Answer 1

您可以使用 CTE 和 RANK() 函数

create procedure yourProcedure (@TheDate datetime = null)
as

if @TheDate is null 
begin
   set @TheDate = getdate()
end

;with cte as(
SELECT 
    P.NAME AS 'Product Name',
    Isnull(Count(DISTINCT O.OrderID), 0) AS 'Orders Count',
    Sum(Isnull(o.ordertotal, 0)) AS 'Orders Total',
    Sum (Isnull(oi.orderitemquantity, 0)) AS 'Item Total'
 FROM 
    Product P
 INNER JOIN 
    OrderItem OI ON OI.ProductID = P.ProductID
 INNER JOIN 
    Orders O ON O.OrderID = OI.OrderID
WHERE
    --here is the limiting to the previous month based off the month passed in
    SomeDateField >= DATEADD(MONTH, DATEDIFF(MONTH, 0, @TheDate)-1, 0)
    and
    SomeDateField < DATEADD(month, DATEDIFF(month, 0, @TheDate), 0)
GROUP BY 
    P.Name)

select
    *
    ,DENSE_RANK() over (order by [Orders Count]) as RK
from cte

DENSE_RANK() 不会跳过数字，而 RANK() 可能取决于您的数据集。

例子

declare @table table (ID int identity (1,1), item int)
insert into @table
values
(1),
(2),
(3),
(3),
(3),
(3),
(4),
(5),
(6)

select 
    * 
    ,rank() over (order by item) TheRank
    ,dense_rank() over (order by item) TheDenseRank
from @table

+----+------+---------+--------------+
| ID | item | TheRank | TheDenseRank |
+----+------+---------+--------------+
|  1 |    1 |       1 |            1 |
|  2 |    2 |       2 |            2 |
|  3 |    3 |       3 |            3 |
|  4 |    3 |       3 |            3 |
|  5 |    3 |       3 |            3 |
|  6 |    3 |       3 |            3 |
|  7 |    4 |       7 |            4 | --notice difference starting here
|  8 |    5 |       8 |            5 |
|  9 |    6 |       9 |            6 |
+----+------+---------+--------------+

此外，这听起来像是家庭作业——如果是，我建议将其放在问题中以防止假设。

SQL 服务器 - 我将如何对上个月的产品进行排名？

SQL Server - How would I rank products from the last month?

sql-server

stored-procedures

rank

window-functions