sql - 如何显示捐赠是否发生在前一年而不是当前？

Question

我正在 Server 2012 中使用以下架构和查询创建年度捐赠报告:

CREATE TABLE Donation
(
   HouseholdID INT, 
   HouseholdName VARCHAR(150), 
   [Donation] REAL, 
   DateOrdered DATE
);

INSERT Donation VALUES
(1,'The Smiths',50,'2011-01-01'),
(1,'The Smiths',75,'2012-02-02'),
(2,'The Wilsons',10,'2011-03-01'),
(2,'The Wilsons',60,'2011-07-01'),
(3,'The Kellys',500,'2012-06-01');

--Params
DECLARE @RunYear   INT=2012
DECLARE @PriorYear INT=@RunYear-1

SELECT 
    [HouseholdID],[HouseholdName],YEAR(DateOrdered) [Year], MAX(Donation) [MaxGift], SUM(Donation) [TotalDonated]
FROM 
    Donation 
WHERE 
    YEAR([DateOrdered]) IN (@RunYear,@PriorYear)
    GROUP BY HouseholdID, [HouseholdName], YEAR(DateOrdered)
    ORDER BY HouseholdID, YEAR(DateOrdered)

我想添加一个像 [DonatedInPriorYearOnly] 这样的 BIT 列，只有当该家庭在上一年(2011 年)有捐款但在运行年(2012 年)没有捐款时，该列才会为 1 .

如何实现？

Answer 1

根据您的 SQLServer 版本，您可以包装摘要查询(在子查询或 CTE 中)并使用 LAG .如果 HouseholdID 和 Year 与 LAG HouseholdID 和(Year - 1)不匹配，则上一年没有捐赠。

大致像这样(未经测试):

SELECT [HouseholdID], [HouseholdName], [Year], [MaxGift], [TotalDonated]
      ,CASE WHEN YEAR = previous_year +1 THEN 1 ELSE 0 END AS DonatedPreviousYear

   FROM ( SELECT [HouseholdID], [HouseholdName], [Year], [MaxGift], [TotalDonated]
                ,LAG(Year, 1, 0) OVER (PARTITION BY HouseholdID ORDER BY Year) AS previous_year

            FROM ( SELECT [HouseholdID],[HouseholdName],YEAR(DateOrdered) [Year], MAX(Donation) [MaxGift], SUM(Donation) [TotalDonated]
                     FROM  Donation 
                     WHERE [DateOrdered] BETWEEN @StartDt AND @EndDt
                     GROUP BY HouseholdID, [HouseholdName], YEAR(DateOrdered)
                     ORDER BY HouseholdID, YEAR(DateOrdered)
                  )
        )