我有一张看起来像这样的表：
id fk_det userid
3 9 name1,name2
6 1 name3
9 2 name4,name5
12 3 name6,name7
我已经学会了后悔以逗号分隔值的方式使用userid的值，所以我想将行分开并最终得到类似
的内容id fk_det userid
3 9 name1
x 9 name2
6 1 name3
9 2 name4
x 2 name5
12 3 name6
x 3 name7
我一直在看这样的事情：
select fk_det, det, LEFT(userid, CHARINDEX(',',userid+',')-1),
STUFF(userid, 1, CHARINDEX(',',userid+','), '')
from global_permissions
但我不确定当userid包含2个以上的项目时，如何使它工作（可能有些项目可能没有，有些可能有多项，只是取决于）
答案 0 :(得分：1)
这是我倾向于使用的：
IF EXISTS (
SELECT 1
FROM dbo.sysobjects
WHERE id = object_id(N'[dbo].[ParseString]')
AND xtype in (N'FN', N'IF', N'TF'))
BEGIN
DROP FUNCTION [dbo].[ParseString]
END
GO
CREATE FUNCTION dbo.ParseString (@String VARCHAR(8000), @Delimiter VARCHAR(10))
RETURNS TABLE
AS
/*******************************************************************************************************
* dbo.ParseString
*
* Creator: magicmike
* Date: 9/12/2006
*
*
* Outline: A set-based string tokenizer
* Takes a string that is delimited by another string (of one or more characters),
* parses it out into tokens and returns the tokens in table format. Leading
* and trailing spaces in each token are removed, and empty tokens are thrown
* away.
*
*
* Usage examples/test cases:
Single-byte delimiter:
select * from dbo.ParseString2('|HDI|TR|YUM|||', '|')
select * from dbo.ParseString2('HDI| || TR |YUM', '|')
select * from dbo.ParseString2(' HDI| || S P A C E S |YUM | ', '|')
select * from dbo.ParseString2('HDI|||TR|YUM', '|')
select * from dbo.ParseString2('', '|')
select * from dbo.ParseString2('YUM', '|')
select * from dbo.ParseString2('||||', '|')
select * from dbo.ParseString2('HDI TR YUM', ' ')
select * from dbo.ParseString2(' HDI| || S P A C E S |YUM | ', ' ') order by Ident
select * from dbo.ParseString2(' HDI| || S P A C E S |YUM | ', ' ') order by StringValue
Multi-byte delimiter:
select * from dbo.ParseString2('HDI and TR', 'and')
select * from dbo.ParseString2('Pebbles and Bamm Bamm', 'and')
select * from dbo.ParseString2('Pebbles and sandbars', 'and')
select * from dbo.ParseString2('Pebbles and sandbars', ' and ')
select * from dbo.ParseString2('Pebbles and sand', 'and')
select * from dbo.ParseString2('Pebbles and sand', ' and ')
*
*
* Notes:
1. A delimiter is optional. If a blank delimiter is given, each byte is returned in it's own row (including spaces).
select * from dbo.ParseString3('|HDI|TR|YUM|||', '')
2. In order to maintain compatibility with SQL 2000, ident is not sequential but can still be used in an order clause
If you are running on SQL2005 or later
SELECT Ident, StringValue FROM
with
SELECT Ident = ROW_NUMBER() OVER (ORDER BY ident), StringValue FROM
*
*
* Modifications
*
*
********************************************************************************************************/
RETURN (
SELECT Ident, StringValue FROM
(
SELECT Num as Ident,
CASE
WHEN DATALENGTH(@delimiter) = 0 or @delimiter IS NULL
THEN LTRIM(SUBSTRING(@string, num, 1)) --replace this line with '' if you prefer it to return nothing when no delimiter is supplied. Remove LTRIM if you want to return spaces when no delimiter is supplied
ELSE
LTRIM(RTRIM(SUBSTRING(@String,
CASE
WHEN (Num = 1 AND SUBSTRING(@String,num ,DATALENGTH(@delimiter)) <> @delimiter) THEN 1
ELSE Num + DATALENGTH(@delimiter)
END,
CASE CHARINDEX(@Delimiter, @String, Num + DATALENGTH(@delimiter))
WHEN 0 THEN LEN(@String) - Num + DATALENGTH(@delimiter)
ELSE CHARINDEX(@Delimiter, @String, Num + DATALENGTH(@delimiter)) - Num -
CASE
WHEN Num > 1 OR (Num = 1 AND SUBSTRING(@String,num ,DATALENGTH(@delimiter)) = @delimiter)
THEN DATALENGTH(@delimiter)
ELSE 0
END
END
)))
End AS StringValue
FROM dbo.Numbers
WHERE Num <= LEN(@String)
AND (
SUBSTRING(@String, Num, DATALENGTH(ISNULL(@delimiter,''))) = @Delimiter
OR Num = 1
OR DATALENGTH(ISNULL(@delimiter,'')) = 0
)
) R WHERE StringValue <> ''
)
您可以这样使用它：
SELECT id, pk_det, V.StringValue as userid
FROM myTable T
OUTER APPLY dbo.ParseString(T.userId) V
UDF需要一个'tally'或Number表，它采用以下模式：
IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 'Numbers')
BEGIN
CREATE TABLE dbo.Numbers
(
Num INT NOT NULL
CONSTRAINT [PKC__Numbers__Num] PRIMARY KEY CLUSTERED (Num) on [PRIMARY]
)
;WITH Nbrs_3( n ) AS ( SELECT 1 UNION SELECT 0 ),
Nbrs_2( n ) AS ( SELECT 1 FROM Nbrs_3 n1 CROSS JOIN Nbrs_3 n2 ),
Nbrs_1( n ) AS ( SELECT 1 FROM Nbrs_2 n1 CROSS JOIN Nbrs_2 n2 ),
Nbrs_0( n ) AS ( SELECT 1 FROM Nbrs_1 n1 CROSS JOIN Nbrs_1 n2 ),
Nbrs ( n ) AS ( SELECT 1 FROM Nbrs_0 n1 CROSS JOIN Nbrs_0 n2 )
INSERT INTO dbo.Numbers(Num)
SELECT n
FROM ( SELECT ROW_NUMBER() OVER (ORDER BY n)
FROM Nbrs ) D ( n )
WHERE n <= 50000 ;
END
Numbers表是您工具集的宝贵补充。引用Adam Machanic：
数字表非常宝贵。我一直都在使用它们 字符串操作，模拟窗口函数，填充测试 包含大量数据的表，消除了游标逻辑等等 没有它们会非常困难的任务。
正如我看到一些人声称的那样，使用数字表是黑客吗？ 不。告诉我另一种有效地做所有事情的方法 表可以。这会浪费空间吗？不会。下面的脚本会用完 每个数据库中大约900 KB的磁盘空间。这绝对是 没有。你最终会得到数百万，甚至数十亿 磁盘空间投资在易于开发和时间方面回归 保存。
答案 1 :(得分：1)
试试这个：）
DECLARE @Name TABLE
(
id INT NULL ,
fk_det INT NULL ,
userid NVARCHAR(100) NULL
)
INSERT INTO @Name
( id, fk_det, userid)
VALUES (3,9,'name1,name2' )
INSERT INTO @Name
( id, fk_det, userid)
VALUES (6,1,'name3' )
INSERT INTO @Name
( id, fk_det, userid)
VALUES (9,2,'name4,name5' )
INSERT INTO @Name
( id, fk_det, userid)
VALUES (12,3,'name6,name7' )
SELECT *
FROM @Name
SELECT id,A.fk_det,
Split.a.value('.', 'VARCHAR(100)') AS String
FROM (SELECT id,fk_det,
CAST ('<M>' + REPLACE(userid, ',', '</M><M>') + '</M>' AS XML) AS String
FROM @Name) AS A CROSS APPLY String.nodes ('/M') AS Split(a);
答案 2 :(得分：0)
作为标准sproc调用的替代方案，您可以随处看到：
with temp as(
select id,fk_det,cast('<comma>'+replace(userid,',','</comma><comma>')+'</comma>' as XMLcomma
from global_permissions
)
select id,fk_det,a.value('comma[1]','varchar(512)')
cross apply temp.XMLcomma.nodes('/comma') t(a)