Question

我的表格中有以下数据

Name Break 
AA    1      
BB    1      
CC           
DD           
EE    1      
FF            
GG    1

现在我想要下面的结果。

规则就像更新名称列中名称列的副本值，直到找到 1 in break 列。

Name Break UpdatedName
AA    1      AA
BB    1      BB
CC           BB
DD           BB
EE    1      EE 
FF           EE 
GG    1      GG

如何获得上述结果？

Answer 1

使用＆＃34;窗口＆＃34;子查询。

IF OBJECT_ID('tempdb..#Names') IS NOT NULL
    DROP TABLE #Names

CREATE TABLE #Names (
    Name VARCHAR(2),
    Breaks INT)

INSERT INTO #Names (
    Name,
    Breaks)
VALUES
    ('A', 1),
    ('B', 1),
    ('C', NULL),
    ('D', NULL),
    ('E', 1),
    ('F', NULL),
    ('G', 1)

SELECT
    N.Name,
    N.Breaks,
    UpdatedName = (SELECT MAX(X.Name) FROM #Names AS X WHERE X.Name <= N.Name AND X.Breaks = 1)
FROM
    #Names AS N

Answer 2

试试这个

DECLARE @Data AS TABLE(Name VARCHAr(10), [Break] INt)
INSERT INTO @Data

SELECT 'AA',1 UNION ALL  
SELECT 'BB',1 UNION ALL     
SELECT 'CC',NULL  UNION ALL     
SELECT 'DD',NULL  UNION ALL     
SELECT 'EE',1 UNION ALL     
SELECT 'FF',NULL  UNION ALL      
SELECT 'GG',1 

SELECT Name,[Break],
      IIF([Break]=1,Name,LAG(Name,1)OVER(ORDER BY  Name)) AS UpdatedName
 FROM @Data

结果/演示http://rextester.com/SGIB7287

Answer 3

您也可以使用嵌套的Select查询，如下所示 的 see live demo

注意：我假设名称不一定按字母顺序排列

; with cte as (select rn=row_number() over (order by (select NULL)), * from tbl) select c1.Name, c1.[Break], updateValue= case when c1.[break] is not null then C1.Name else ( select TOP 1 c2.Name from cte c2 where c2.rn<c1.rn and c2.[break] is NOT NULL order BY rn desc ) end from cte c1 order by c1.rn

复制相同的值，直到SQL Server中出现新值

3 个答案: