SQL select 已知相同字符之间的字符串

Question

我有代码 select 是典型字符串中第一个和第二个“/”之间的字符串，可能如下所示：

2014-Ceilings/Ceilings/Repair/Asbestos/Supalux

下面的代码正确地 returns 上面例子中的值 'Ceilings'。

SELECT 
REPLACE (LEFT(SUBSTRING(ElementPath,CHARINDEX
            ('/',ElementPath)+1,LEN(ElementPath)),CHARINDEX
        ('/',SUBSTRING(ElementPath, CHARINDEX
                ('/',ElementPath)+1,LEN(ElementPath)))),'/','')
FROM K2_Master.dbo.tbElement

如何将它修改为 select 第二个和第三个 '/' 之间的字符串 return 值 'Repair'?

Answer 1

检查这个小技巧是否可行：

DECLARE @String VARCHAR(100)= '2014-Ceilings/Ceilings/Repair/Asbestos/Supalux'

SET @String = '<N>' + Replace(@String, '/', '</N><N>')
              + '</N>'

SELECT c.value('/N[1]', 'varchar(30)'),
       c.value('/N[2]', 'varchar(30)'),
       c.value('/N[3]', 'varchar(30)')
FROM   (SELECT Cast(@String AS XML)) t(c) 

SELECT c1.value('.', 'varchar(30)')
FROM   (SELECT CAST(@String AS XML)) t(c)
       CROSS APPLY c.nodes('/N') AS t1(c1) 

SELECT value
FROM   (SELECT c1.value('.', 'varchar(30)') AS value,
               ROW_NUMBER()
                 OVER(
                   ORDER BY (SELECT 1))     rn
        FROM   (SELECT Cast(@String AS XML)) t(c)
               CROSS APPLY c.nodes('/N') AS t1(c1)) temp
WHERE  rn = 3

你的情况

SELECT c.value('/N[1]', 'varchar(30)'),
       c.value('/N[2]', 'varchar(30)'),
       c.value('/N[3]', 'varchar(30)')
FROM   (SELECT Cast ('<N>' + Replace( Replace (ElementPath, '/', '</N><N>'),'&','&amp;')
                     + '</N>' AS XML)
        FROM   K2_Master.dbo.tbElement) t(c)

Answer 2

我追问了你的问题，得出了一个冗长的结果..

DECLARE @a VARCHAR(40) = '2014-Ceilings/Ceilings/Repair/Asbestos/Supalux'

SELECT      @a
            ,LEFT(
            SUBSTRING(SUBSTRING(@a,CHARINDEX('/',@a,1)+1,LEN(@a)),CHARINDEX('/',SUBSTRING(@a,CHARINDEX('/',@a,1)+1,LEN(@a)),1)+1,LEN(SUBSTRING(@a,CHARINDEX('/',@a,1)+1,LEN(@a)))),
            CHARINDEX('/',SUBSTRING(SUBSTRING(@a,CHARINDEX('/',@a,1)+1,LEN(@a)),CHARINDEX('/',SUBSTRING(@a,CHARINDEX('/',@a,1)+1,LEN(@a)),1)+1,LEN(SUBSTRING(@a,CHARINDEX('/',@a,1)+1,LEN(@a)))),1) - 1
            )

结果：

回复你的评论。

DECLARE @String VARCHAR(100)= '2014-Ceilings/Ceilings/Repair/Asbestos/Supalux',
        @value INT = 2
DECLARE @itra INT = 1

WHILE @itra <= @value
BEGIN 
    SET @String = (SELECT SUBSTRING(@String,CHARINDEX('/',@String,1)+1,LEN(@String)))
    --SELECT @String
    SET @itra = @itra + 1
END 

SELECT LEFT(@String, CHARINDEX('/',@String,1) - 1)

把'/'的位置写成@value然后看结果。对于上面的sql，结果是Repair。如果你给出 @value = 3, 结果是 Asbestos

SQL select 已知相同字符之间的字符串

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sql-server-2008-r2