根据ProvinceNo(Branch)填写比率表中的缺失值？

Question

IF OBJECT_ID('tempdb..#ReflectionRatio') IS NOT NULL DROP TABLE #ReflectionRatio
CREATE TABLE #ReflectionRatio(
    [ReflectionRatioKey] [int] IDENTITY(1,1) NOT NULL,
    [StartDate] [date] NULL,
    [ProvinceNo] [nvarchar](3) NULL,
    [Rate] [float] NULL,
    [Period] [nvarchar](10) NULL
)

INSERT INTO #ReflectionRatio VALUES
(1,'2005-01-01','712',0.0002,'2005-01'),
(2,'2005-01-01','750',0.0661,'2005-01'),
(3,'2019-06-01','712',0.000114,'2019-06'),
(4,'2019-06-01','750',0.05972,'2019-06'),
(5,'2020-05-31','712',0.0002,'2020-05'),
(6,'2020-05-01','750',0.0661,'2020-05'),
(7,'2023-05-02','712',0.000242,'2023-05'),
(8,'2023-05-02','750',0.069265,'2023-05')

我需要根据下面定义的规则填写缺失值： 填写日期期间 : 2005-01-01 / 2023-12-31

-- 规则 1：如果特定省份缺少比率，则取上一个最近的比率：

例如：对于 750 个省份，从 2019-07 期间到 2020-05，记录应为：

(IDENTITYCOLUMN,'2019-07-01','750',0.05972,'2019-07'),
(IDENTITYCOLUMN,'2019-08-01','750',0.05972,'2019-08'),
(IDENTITYCOLUMN,'2019-09-01','750',0.05972,'2019-09'),
........
........
(IDENTITYCOLUMN,'2020-04-01','750',0.05972,'2020-04')

--规则2：一个省内所有比率值都为0.0，则取之前所有省份的比率。

注：其实我有很多省份，不只是712和750！

我尝试使用窗口函数（LEAD 和 LAG）来解决它，但我只设法获取第一个下一条记录和上一条记录。

ProvinceNo-750 以及从 2019-07 期间到 2023-12，记录应为：

(IDENTITYCOLUMN,'2019-07-01','750',0.05972,'2019-07'),
(IDENTITYCOLUMN,'2019-08-01','750',0.05972,'2019-08'),
(IDENTITYCOLUMN,'2019-09-01','750',0.05972,'2019-09'),
........
........
(IDENTITYCOLUMN,'2020-04-01','750',0.05972,'2020-04')
(IDENTITYCOLUMN,'2020-05-01','750',0.0661,'2020-05')
(IDENTITYCOLUMN,'2020-06-01','750',0.0661,'2020-06')
.........
.........
(IDENTITYCOLUMN,'2023-04-01','750',0.0661,'2023-04')
(IDENTITYCOLUMN,'2023-05-02','750',0.069265,'2023-05')
(IDENTITYCOLUMN,'2023-06-02','750',0.069265,'2023-06')
.........
.........
(IDENTITYCOLUMN,'2023-12-02','750',0.069265,'2023-12')

我感谢任何帮助，谢谢！

Answer 1

下面的解决方案是使用

tally

表。使用

lead()

获取下一个

StartDate

并找出月份的差异即可得出缺失的行数。将其加入到

tally

表 (

numbers

) 中，您将获得缺失的行。

对于条件

ratio with 0.0

，只需将其视为缺失行并从cte中排除它

ReflectionRatio

with condition

where r.Rate <> 0

对于这种情况，您需要对表执行更新而不是插入。

with ReflectionRatio as
(
  select ProvinceNo, StartDate, 
         NextDate = lead(StartDate) over (partition by r.ProvinceNo order by r.StartDate),
         Rate
  from   #ReflectionRatio r  
)
select r.ProvinceNo,
       StartDate = dateadd(month, n, r.StartDate),
       r.Rate
from   ReflectionRatio r
       inner join numbers n  on  n.n >= 1
                             and n.n <  datediff(month, r.StartDate, r.NextDate)