排行榜处理示例.sql

--图书销售数据表
CREATE TABLE tb(
Books nvarchar(30), --书名
Date datetime,     --销售日期
Sales int)         --销售数量
--生成测试数据
INSERT tb SELECT
   CHAR(65+RAND(CHECKSUM(NEWID()))*25),
   DATEADD(Day,1-RAND(CHECKSUM(NEWID()))*500,GETDATE()),
   RAND(CHECKSUM(NEWID()))*360
FROM sysobjects a,sysobjects b
--显示数据
SELECT * FROM tb
GO

--排行榜处理的存储过程
CREATE PROC p_Qry
@Type nchar(1)=N'日', --排行榜处理类型(日、周、月、季、年)
@Date datetime=null,   --排行榜日期,不指定为当前日期
@TopN int=10          --记录数
AS
SET NOCOUNT ON
DECLARE @p_dt_begin datetime,@dt_begin datetime

--参数检测
IF CHARINDEX(@Type,N'日周月季年')=0
   SET @Type=N'日'
IF @Date IS NULL
   SET @Date=CONVERT(char(10),GETDATE(),120)
ELSE
   SET @Date=CONVERT(char(10),@Date,120)
IF ISNULL(@TopN,0)<1
   SET @TopN=10

--根据@Type决定计算的起始日期
IF @Type=N'日'
   SELECT
       @dt_begin=@Date,
       @Date=DATEADD(Day,1,@Date),
       @p_dt_begin=DATEADD(Day,-1,@dt_begin)
ELSE IF @Type=N'周'
   SELECT
       @dt_begin=DATEADD(Day,-(DATEPART(Weekday,@Date)+@@DATEFIRST-2)%7,@Date),
       @Date=DATEADD(Day,7,@dt_begin),
       @p_dt_begin=DATEADD(Day,-7,@dt_begin)
ELSE IF @Type=N'月'
   SELECT
       @dt_begin=CONVERT(char(8),@Date,120)+'01',
       @Date=DATEADD(Month,1,@dt_begin),
       @p_dt_begin=DATEADD(Month,-1,@dt_begin)
ELSE IF @Type=N'季'
   SELECT
       @dt_begin=CONVERT(char(8),
           DATEADD(Month,DATEPART(Quarter,@Date)*3-Month(@Date)-2,@Date),
           120)+'1',
       @Date=DATEADD(Month,3,@dt_begin),
       @p_dt_begin=DATEADD(Month,-3,@dt_begin)
ELSE
   SELECT
       @dt_begin=CONVERT(char(5),@Date,120)+'01-01',
       @Date=DATEADD(Year,1,@dt_begin),
       @p_dt_begin=DATEADD(Year,-1,@dt_begin)

--取排名数据到临时表
SET ROWCOUNT @TopN
--最新名称
SELECT Books,Sales_Amount=SUM(Sales)
INTO #1 FROM tb
WHERE Date>=@dt_begin AND Date<@Date
GROUP BY Books
ORDER BY Sales_Amount DESC
--上期名次
SELECT Books,Sales_Amount=SUM(Sales)
INTO #2 FROM tb
WHERE Date>=@p_dt_begin AND Date<@dt_begin
GROUP BY Books
ORDER BY Sales_Amount DESC

--显示结果
SELECT a.Books,a.Sales_Amount,a.Place,
   Description=CASE
       WHEN b.Books IS NULL THEN N'↑新上榜'
       WHEN a.Place=b.Place THEN N'－'
       WHEN a.Place>b.Place THEN N'↓'+RTRIM(a.Place-b.Place)+N'位'
       ELSE N'↑'+RTRIM(b.Place-a.Place)+N'位' END,b.*
FROM(
   SELECT Books,Sales_Amount,
       Place=(SELECT COUNT(Sales_Amount) FROM #1 WHERE Sales_Amount>aa.Sales_Amount)+1
   FROM #1 aa
)a LEFT JOIN(
   SELECT Books,
       Place=(SELECT COUNT(Sales_Amount) FROM #2 WHERE Sales_Amount>aa.Sales_Amount)+1
   FROM #2 aa
)b ON a.Books=b.Books
ORDER BY a.Place
GO

--调用
EXEC p_Qry N'日'
EXEC p_Qry N'周'
EXEC p_Qry N'月'
EXEC p_Qry N'季'
EXEC p_Qry N'年'

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