根据特定行

Question

大家好，我需要你的帮助：

我需要根据一些特定的行在sql server中填充一个额外的列（Directory）。为此，我需要评估列（文件名）并在列（目录）上复制它，直到关键字更改为止。所以原来的表是这样的：

这就是我需要完成的事情：

我可以使用CTE吗？怎么样？

提前致谢！

Answer 1

如果directory命名格式与您的样本数据一致，则此处为单向

SELECT id,Filename,
       Directory = Min(Filename)OVER(partition BY grp)
FROM   (SELECT *,
                grp= Sum(CASE WHEN Filename LIKE '-%' THEN 1 ELSE 0 END)
                      OVER(ORDER BY id ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)               
        FROM   Yourtable) a 

另一种较少依赖于命名约定的方法

SELECT id,
       Filename,
       Directory = Max(iDirectory)OVER(partition BY grp)
FROM   (SELECT Id,
               Filename,
               grp,
               iDirectory=CASE WHEN Row_number() OVER(partition BY grp ORDER BY id) = 1 THEN Filename ELSE NULL END
        FROM   (SELECT *,
                       grp= Sum(CASE WHEN Filename LIKE '-%' THEN 1 ELSE 0 END)
                              OVER(ORDER BY id ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)
                FROM   #test) a)b 

Answer 2

declare  @tt table (id int identity(1,1), [FileName] varchar(50), DirectoryName varchar(50))
insert into @tt([FileName]) values
('- Directory 1')
,('File a')
,('File b')
,('File c')
,('- Directory 2')
,('File d')
,('File e')
,('File f')
,('File g')

SELECT A.ID, A.[FILENAME],
    (
        SELECT TOP 1 [FILENAME] FROM @TT AS B 
        WHERE [FILENAME] LIKE '- DIRECTORY%'
        AND B.ID <= A.ID
        ORDER BY B.ID DESC
    ) AS DIRECTORYNAME
FROM @TT AS A