sql服务器滚动12个月总计与日期差距

Question

假设我有一个表，指出每个销售代表在特定月份销售的物品数量。但是，在没有销售的情况下，几个月内不会有一个特定的人排队。例如

rep_id  month_yr  num_sales  
1   01/01/2012 3  
1   05/01/2012 1  
1   11/01/2012 1  
2   02/01/2012 2  
2   05/01/2012 1 

我希望能够创建一个查询，显示每个rep_id和所有可能个月（01/01/2012，02/01/2012，通过等电流）一个连续12个月销量总和，像这样：

rep_id  month_yr  R12_Sum  
1   11/01/2012 5  
1   12/01/2012 5  
1   01/01/2013 5  
1   02/01/2013 2 

我在网上找到了一些例子，但我遇到的问题是我错过了每个rep_id的一些日期。我是否需要交叉加入或什么？

Answer 1

为了解决这个问题，你需要具有所有年/月组合的驱动器表。然后，你需要为每个代表创建这个。

然后解决方案是将实际数据连接到此驱动程序并汇总所需的时间段。以下是查询：

with months as (
    select 1 as mon union all select 2 union all select 3 union all select 4 union all 
    select 5 as mon union all select 6 union all select 7 union all select 8 union all 
    select 9 as mon union all select 10 union all select 11 union all select 12 
    ), 
    years as (select 2010 as yr union all select 2011 union all select 2012 union all select 2013 
    ), 
    monthyears as (
    select yr, mon, yr*12+mon as yrmon 
    from months cross join years 
    ), 
    rmy as (
    select * 
    from monthyears my cross join 
      (select distinct rep_id from t 
     ) r 
    ) 
select rmy.rep_id, rmy.yr, rmy.mon, SUM(t.num_sales) as r12_sum 
from rmy join 
    t 
    on rmy.rep_id = t.rep_id and 
     t.year(month_yr)*12 + month(month_yr) between rmy.yrmon - 11 and rmy.yrmon 
group by rmy.rep_id, rmy.yr, rmy.mon 
order by 1, 2, 3 

这没有经过测试，所以它可能有语法错误。此外，它不会将年/月组合转换回日期，并将值留在单独的列中。

Answer 2

这里是一个解决方案：

SELECT 
    a.rep_id 
    ,a.month_yr 
    ,SUM(b.R12_Sum) AS R12_TTM 
FROM YourTable a 
    LEFT OUTER JOIN YourTable b 
    ON a.rep_id = b.rep_id 
    AND a.month_yr <= b.month_yr 
    AND a.month_yr >= DATEADD(MONTH, -11, b.month_yr) 
GROUP BY 
    a.rep_id 
    ,a.month_yr 

Answer 3

这当然不是漂亮，但比CTE更简单，数字表或自联接：

DECLARE @startdt DATETIME 

SET @startdt = '2012-01-01' 

SELECT rep_id, YEAR(month_yr), MONTH(month_yr), SUM(num_sales) 
FROM MyTable WHERE month_yr >= @startdt AND month_yr < DATEADD(MONTH,1,@startdt) 

UNION ALL 

SELECT rep_id, YEAR(month_yr), MONTH(month_yr), SUM(num_sales) 
FROM MyTable WHERE month_yr >= DATEADD(MONTH,1,@startdt) AND month_yr < DATEADD(MONTH,2,@startdt) 

UNION ALL 

SELECT rep_id, YEAR(month_yr), MONTH(month_yr), SUM(num_sales) 
FROM MyTable WHERE month_yr >= DATEADD(MONTH,2,@startdt) AND month_yr < DATEADD(MONTH,3,@startdt) 

UNION ALL 

SELECT rep_id, YEAR(month_yr), MONTH(month_yr), SUM(num_sales) 
FROM MyTable WHERE month_yr >= DATEADD(MONTH,3,@startdt) AND month_yr < DATEADD(MONTH,4,@startdt) 

UNION ALL 

etc etc 

Answer 4

下面演示了使用CTE生成日期的表格，并生成使用CTE的总结报告。当销售代表没有适用的销售时，他们将被忽略。

尝试跳转报告参数，例如设置@RollingMonths到1，以获得更多娱乐。

-- Sample data. 
declare @Sales as Table (rep_id Int, month_yr Date, num_sales Int); 
insert into @Sales (rep_id, month_yr, num_sales) values 
    (1, '01/01/2012', 3), 
    (1, '05/01/2012', 1), 
    (1, '11/01/2012', 1), 
    (2, '02/01/2012', 1), 
    (2, '05/01/2012', 2); 
select * from @Sales; 

-- Reporting parameters. 
declare @ReportEnd as Date = DateAdd(day, 1 - Day(GetDate()), GetDate()); -- The first of the current month. 
declare @ReportMonths as Int = 6; -- Number of months to report. 
declare @RollingMonths as Int = 12; -- Number of months in rolling sums. 

-- Report. 
-- A CTE generates a table of month/year combinations covering the desired reporting time period. 
with ReportingIntervals as (
    select DateAdd(month, 1 - @ReportMonths, @ReportEnd) as ReportingInterval, 
    DateAdd(month, 1 - @RollingMonths, DateAdd(month, 1 - @ReportMonths, @ReportEnd)) as FirstRollingMonth 
    union all 
    select DateAdd(month, 1, ReportingInterval), DateAdd(month, 1, FirstRollingMonth) 
    from ReportingIntervals 
    where ReportingInterval < @ReportEnd) 
    -- Join the CTE with the sample data and summarize. 
    select RI.ReportingInterval, S.rep_id, Sum(S.num_sales) as R12_Sum 
    from ReportingIntervals as RI left outer join 
     @Sales as S on RI.FirstRollingMonth <= S.month_yr and S.month_yr <= RI.ReportingInterval 
    group by RI.ReportingInterval, S.rep_id 
    order by RI.ReportingInterval, S.rep_id