排名趋势公式

use tempdb
go
if object_id(‘PersonalSalesRank‘) Is not null drop Table PersonalSalesRank
go
create table PersonalSalesRank(Name nvarchar(20),YM date, SalesQty int ,RankNr int,RankTrend int)
go
set nocount on
insert into dbo.PersonalSalesRank ( Name , YM , SalesQty  )
    values    
--2017-01
    (‘Kent‘,‘20170101‘,400),
    (‘John‘,‘20170101‘,758),
    (‘Rob‘,‘20170101‘,365),
    (‘Ruben‘,‘20170101‘,487),
    (‘Andy‘,‘20170101‘,651),
--2017-02
    (‘Andy‘,‘20170201‘,668),
    (‘Christy‘,‘20170201‘,541),
    (‘Kent‘,‘20170201‘,712),
    (‘Ruben‘,‘20170201‘,729),
    (‘Rob‘,‘20170201‘,365),
    (‘John‘,‘20170201‘,465),
--2017-03
    (‘Andy‘,‘20170301‘,651),
    (‘Christy‘,‘20170301‘,588),
    (‘Kent‘,‘20170301‘,769),
    (‘Ruben‘,‘20170301‘,752),
    (‘Rob‘,‘20170301‘,552),
    (‘John‘,‘20170301‘,421)

go

if object_id(‘fn_RankTrend‘) Is not null drop function  fn_RankTrend
go
/********************************************************************************************
%% Program Name    :fn_RankTrend
%% Author        : Andy.Wei
%% Description    :
%% InParameter    :
%% OutParameter    :
%% Created Date    : 2017-05-12
%% Revision History :
%% Modified Date Modified By  version Description
%%
********************************************************************************************/
create function fn_RankTrend
(
    @CurrentRankNr int,
    @LastRankNr int,
    @LastRankTrend int
)
returns int 
as
begin

    return(isnull(sign( @LastRankNr - @CurrentRankNr) + @LastRankTrend * ( 1 - abs(sign( sign(@LastRankNr - @CurrentRankNr)^sign(@LastRankTrend) )) ) ,0))
end
go

--排名
;with cte_Rank as 
(
    select  RankNr,dense_rank() over(partition by YM order by SalesQty desc) as RankNr_1 from dbo.PersonalSalesRank
)
update a  
    set a.RankNr=a.RankNr_1
    from cte_Rank a

--更新排名趋势
declare @YM date=‘20170101‘
while(1=1)
begin
    update a 
        set a.RankTrend=dbo.fn_RankTrend(a.RankNr,b.RankNr,b.RankTrend)
        from dbo.PersonalSalesRank a 
            left join dbo.PersonalSalesRank b on b.Name=a.Name
                and b.YM=dateadd(month,-1,@YM)
        where a.YM=@YM;
    if @@ROWCOUNT =0 break;
    print @YM
    set @YM=dateadd(month,1,@YM)
end

select    name as [姓名],
        convert(char(7),a.YM,121) as [月份],
        a.SalesQty as [销量],
        convert(nvarchar(20),N‘第 ‘+rtrim(a.RankNr)+N‘ 名‘) as [排名],
        case sign(a.RankTrend)
            when -1 then N‘↓‘
            when 1  then N‘↑‘
            else N‘‘
        end as [排名升降],
        case 
            when a.RankTrend>=2 then N‘连续‘+rtrim(abs(a.RankTrend))+N‘月‘
            else N‘‘
        end as [连续上升],
        case 
            when a.RankTrend<=-2 then N‘连续‘+rtrim(abs(a.RankTrend))+N‘月‘
            else N‘‘
        end as [连续下降]
    from dbo.PersonalSalesRank a 
    order by 2,3 desc
go