如何将逗号分隔值拆分为列

Question

我有一张这样的桌子

Value   String
-------------------
1       Cleo, Smith

我想将逗号分隔的字符串分成两列

Value  Name Surname
-------------------
1      Cleo   Smith

我只需要两个固定的额外列

Answer 1

您的目的可以使用以下查询解决 -

Select Value  , Substring(FullName, 1,Charindex(',', FullName)-1) as Name,
Substring(FullName, Charindex(',', FullName)+1, LEN(FullName)) as  Surname
from Table1

在sql server中没有现成的Split函数,所以我们需要创建用户定义的函数.

CREATE FUNCTION Split (
      @InputString                  VARCHAR(8000),
      @Delimiter                    VARCHAR(50)
)

RETURNS @Items TABLE (
      Item                          VARCHAR(8000)
)

AS
BEGIN
      IF @Delimiter = ' '
      BEGIN
            SET @Delimiter = ','
            SET @InputString = REPLACE(@InputString, ' ', @Delimiter)
      END

      IF (@Delimiter IS NULL OR @Delimiter = '')
            SET @Delimiter = ','

--INSERT INTO @Items VALUES (@Delimiter) -- Diagnostic
--INSERT INTO @Items VALUES (@InputString) -- Diagnostic

      DECLARE @Item           VARCHAR(8000)
      DECLARE @ItemList       VARCHAR(8000)
      DECLARE @DelimIndex     INT

      SET @ItemList = @InputString
      SET @DelimIndex = CHARINDEX(@Delimiter, @ItemList, 0)
      WHILE (@DelimIndex != 0)
      BEGIN
            SET @Item = SUBSTRING(@ItemList, 0, @DelimIndex)
            INSERT INTO @Items VALUES (@Item)

            -- Set @ItemList = @ItemList minus one less item
            SET @ItemList = SUBSTRING(@ItemList, @DelimIndex+1, LEN(@ItemList)-@DelimIndex)
            SET @DelimIndex = CHARINDEX(@Delimiter, @ItemList, 0)
      END -- End WHILE

      IF @Item IS NOT NULL -- At least one delimiter was encountered in @InputString
      BEGIN
            SET @Item = @ItemList
            INSERT INTO @Items VALUES (@Item)
      END

      -- No delimiters were encountered in @InputString, so just return @InputString
      ELSE INSERT INTO @Items VALUES (@InputString)

      RETURN

END -- End Function
GO

---- Set Permissions
--GRANT SELECT ON Split TO UserRole1
--GRANT SELECT ON Split TO UserRole2
--GO

Answer 2

;WITH Split_Names (Value,Name, xmlname)
AS
(
    SELECT Value,
    Name,
    CONVERT(XML,'<Names><name>'  
    + REPLACE(Name,',', '</name><name>') + '</name></Names>') AS xmlname
      FROM tblnames
)

 SELECT Value,      
 xmlname.value('/Names[1]/name[1]','varchar(100)') AS Name,    
 xmlname.value('/Names[1]/name[2]','varchar(100)') AS Surname
 FROM Split_Names

并查看以下链接以供参考

http://jahaines.blogspot.in/2009/06/converting-delimited-string-of-values.html

Answer 3

xml基础答案简单而干净

参考这个

DECLARE @S varchar(max),
        @Split char(1),
        @X xml

SELECT @S = 'ab,cd,ef,gh,ij',
       @Split = ','

SELECT @X = CONVERT(xml,' <root> <myvalue>' +
REPLACE(@S,@Split,'</myvalue> <myvalue>') + '</myvalue>   </root> ')

SELECT  T.c.value('.','varchar(20)'),              --retrieve ALL values at once
  T.c.value('(/root/myvalue)[1]','VARCHAR(20)')  , --retrieve index 1 only, which is the 'ab'
  T.c.value('(/root/myvalue)[2]','VARCHAR(20)')
 FROM @X.nodes('/root/myvalue') T(c)

Answer 4

我觉得这很酷

SELECT value,
    PARSENAME(REPLACE(String,',','.'),2) 'Name' ,
    PARSENAME(REPLACE(String,',','.'),1) 'Sur Name'
FROM table WITH (NOLOCK)

Answer 5

随着交叉申请

select ParsedData.* 
from MyTable mt
cross apply ( select str = mt.String + ',,' ) f1
cross apply ( select p1 = charindex( ',', str ) ) ap1
cross apply ( select p2 = charindex( ',', str, p1 + 1 ) ) ap2
cross apply ( select Nmame = substring( str, 1, p1-1 )                   
                 , Surname = substring( str, p1+1, p2-p1-1 )
          ) ParsedData

Answer 6

有多种方法可以解决这个问题,并且已经提出了许多不同的方法.最简单的方法是使用LEFT/ SUBSTRING和其他字符串函数来实现所需的结果.

样本数据

DECLARE @tbl1 TABLE (Value INT,String VARCHAR(MAX))

INSERT INTO @tbl1 VALUES(1,'Cleo, Smith');
INSERT INTO @tbl1 VALUES(2,'John, Mathew');

使用字符串函数 LEFT

SELECT
    Value,
    LEFT(String,CHARINDEX(',',String)-1) as Fname,
    LTRIM(RIGHT(String,LEN(String) - CHARINDEX(',',String) )) AS Lname
FROM @tbl1

如果String中有更多2个项,则此方法将失败.在这种情况下,我们可以使用拆分器,然后使用PIVOT或将字符串转换为a XML并用于.nodes获取字符串项.XMLaads和bvr在他们的解决方案中详细介绍了基于解决方案的解决方案.

使用分离器的这个问题的答案,所有使用WHILE都是低效的分裂.检查此性能比较.DelimitedSplit8K由Jeff Moden创建的最好的分离器之一.你可以在这里阅读更多相关信息

拆分器 PIVOT

DECLARE @tbl1 TABLE (Value INT,String VARCHAR(MAX))

INSERT INTO @tbl1 VALUES(1,'Cleo, Smith');
INSERT INTO @tbl1 VALUES(2,'John, Mathew');


SELECT t3.Value,[1] as Fname,[2] as Lname
FROM @tbl1 as t1
CROSS APPLY [dbo].[DelimitedSplit8K](String,',') as t2
PIVOT(MAX(Item) FOR ItemNumber IN ([1],[2])) as t3

产量

Value   Fname   Lname
1   Cleo    Smith
2   John    Mathew

DelimitedSplit8K 杰夫莫登

CREATE FUNCTION [dbo].[DelimitedSplit8K]
/**********************************************************************************************************************
 Purpose:
 Split a given string at a given delimiter and return a list of the split elements (items).

 Notes:
 1.  Leading a trailing delimiters are treated as if an empty string element were present.
 2.  Consecutive delimiters are treated as if an empty string element were present between them.
 3.  Except when spaces are used as a delimiter, all spaces present in each element are preserved.

 Returns:
 iTVF containing the following:
 ItemNumber = Element position of Item as a BIGINT (not converted to INT to eliminate a CAST)
 Item       = Element value as a VARCHAR(8000)

 Statistics on this function may be found at the following URL:
 http://www.sqlservercentral.com/Forums/Topic1101315-203-4.aspx

 CROSS APPLY Usage Examples and Tests:
--=====================================================================================================================
-- TEST 1:
-- This tests for various possible conditions in a string using a comma as the delimiter.  The expected results are
-- laid out in the comments
--=====================================================================================================================
--===== Conditionally drop the test tables to make reruns easier for testing.
     -- (this is NOT a part of the solution)
     IF OBJECT_ID('tempdb..#JBMTest') IS NOT NULL DROP TABLE #JBMTest
;
--===== Create and populate a test table on the fly (this is NOT a part of the solution).
     -- In the following comments, "b" is a blank and "E" is an element in the left to right order.
     -- Double Quotes are used to encapsulate the output of "Item" so that you can see that all blanks
     -- are preserved no matter where they may appear.
 SELECT *
   INTO #JBMTest
   FROM (                                               --# & type of Return Row(s)
         SELECT  0, NULL                      UNION ALL --1 NULL
         SELECT  1, SPACE(0)                  UNION ALL --1 b (Empty String)
         SELECT  2, SPACE(1)                  UNION ALL --1 b (1 space)
         SELECT  3, SPACE(5)                  UNION ALL --1 b (5 spaces)
         SELECT  4, ','                       UNION ALL --2 b b (both are empty strings)
         SELECT  5, '55555'                   UNION ALL --1 E
         SELECT  6, ',55555'                  UNION ALL --2 b E
         SELECT  7, ',55555,'                 UNION ALL --3 b E b
         SELECT  8, '55555,'                  UNION ALL --2 b B
         SELECT  9, '55555,1'                 UNION ALL --2 E E
         SELECT 10, '1,55555'                 UNION ALL --2 E E
         SELECT 11, '55555,4444,333,22,1'     UNION ALL --5 E E E E E 
         SELECT 12, '55555,4444,,333,22,1'    UNION ALL --6 E E b E E E
         SELECT 13, ',55555,4444,,333,22,1,'  UNION ALL --8 b E E b E E E b
         SELECT 14, ',55555,4444,,,333,22,1,' UNION ALL --9 b E E b b E E E b
         SELECT 15, ' 4444,55555 '            UNION ALL --2 E (w/Leading Space) E (w/Trailing Space)
         SELECT 16, 'This,is,a,test.'                   --E E E E
        ) d (SomeID, SomeValue)
;
--===== Split the CSV column for the whole table using CROSS APPLY (this is the solution)
 SELECT test.SomeID, test.SomeValue, split.ItemNumber, Item = QUOTENAME(split.Item,'"')
   FROM #JBMTest test
  CROSS APPLY dbo.DelimitedSplit8K(test.SomeValue,',') split
;
--=====================================================================================================================
-- TEST 2:
-- This tests for various "alpha" splits and COLLATION using all ASCII characters from 0 to 255 as a delimiter against
-- a given string.  Note that not all of the delimiters will be visible and some will show up as tiny squares because
-- they are "control" characters.  More specifically, this test will show you what happens to various non-accented 
-- letters for your given collation depending on the delimiter you chose.
--=====================================================================================================================
WITH 
cteBuildAllCharacters (String,Delimiter) AS 
(
 SELECT TOP 256 
        'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789',
        CHAR(ROW_NUMBER() OVER (ORDER BY (SELECT NULL))-1)
   FROM master.sys.all_columns
)
 SELECT ASCII_Value = ASCII(c.Delimiter), c.Delimiter, split.ItemNumber, Item = QUOTENAME(split.Item,'"')
   FROM cteBuildAllCharacters c
  CROSS APPLY dbo.DelimitedSplit8K(c.String,c.Delimiter) split
  ORDER BY ASCII_Value, split.ItemNumber
;
-----------------------------------------------------------------------------------------------------------------------
 Other Notes:
 1. Optimized for VARCHAR(8000) or less.  No testing or error reporting for truncation at 8000 characters is done.
 2. Optimized for single character delimiter.  Multi-character delimiters should be resolvedexternally from this 
    function.
 3. Optimized for use with CROSS APPLY.
 4. Does not "trim" elements just in case leading or trailing blanks are intended.
 5. If you don't know how a Tally table can be used to replace loops, please see the following...
    http://www.sqlservercentral.com/articles/T-SQL/62867/
 6. Changing this function to use NVARCHAR(MAX) will cause it to run twice as slow.  It's just the nature of 
    VARCHAR(MAX) whether it fits in-row or not.
 7. Multi-machine testing for the method of using UNPIVOT instead of 10 SELECT/UNION ALLs shows that the UNPIVOT method
    is quite machine dependent and can slow things down quite a bit.
-----------------------------------------------------------------------------------------------------------------------
 Credits:
 This code is the product of many people's efforts including but not limited to the following:
 cteTally concept originally by Iztek Ben Gan and "decimalized" by Lynn Pettis (and others) for a bit of extra speed
 and finally redacted by Jeff Moden for a different slant on readability and compactness. Hat's off to Paul White for
 his simple explanations of CROSS APPLY and for his detailed testing efforts. Last but not least, thanks to
 Ron "BitBucket" McCullough and Wayne Sheffield for their extreme performance testing across multiple machines and
 versions of SQL Server.  The latest improvement brought an additional 15-20% improvement over Rev 05.  Special thanks
 to "Nadrek" and "peter-757102" (aka Peter de Heer) for bringing such improvements to light.  Nadrek's original
 improvement brought about a 10% performance gain and Peter followed that up with the content of Rev 07.  

 I also thank whoever wrote the first article I ever saw on "numbers tables" which is located at the following URL
 and to Adam Machanic for leading me to it many years ago.
 http://sqlserver2000.databases.aspfaq.com/why-should-i-consider-using-an-auxiliary-numbers-table.html
-----------------------------------------------------------------------------------------------------------------------
 Revision History:
 Rev 00 - 20 Jan 2010 - Concept for inline cteTally: Lynn Pettis and others.
                        Redaction/Implementation: Jeff Moden 
        - Base 10 redaction and reduction for CTE.  (Total rewrite)

 Rev 01 - 13 Mar 2010 - Jeff Moden
        - Removed one additional concatenation and one subtraction from the SUBSTRING in the SELECT List for that tiny
          bit of extra speed.

 Rev 02 - 14 Apr 2010 - Jeff Moden
        - No code changes.  Added CROSS APPLY usage example to the header, some additional credits, and extra 
          documentation.

 Rev 03 - 18 Apr 2010 - Jeff Moden
        - No code changes.  Added notes 7, 8, and 9 about certain "optimizations" that don't actually work for this
          type of function.

 Rev 04 - 29 Jun 2010 - Jeff Moden
        - Added WITH SCHEMABINDING thanks to a note by Paul White.  This prevents an unnecessary "Table Spool" when the
          function is used in an UPDATE statement even though the function makes no external references.

 Rev 05 - 02 Apr 2011 - Jeff Moden
        - Rewritten for extreme performance improvement especially for larger strings approaching the 8K boundary and
          for strings that have wider elements.  The redaction of this code involved removing ALL concatenation of 
          delimiters, optimization of the maximum "N" value by using TOP instead of including it in the WHERE clause,
          and the reduction of all previous calculations (thanks to the switch to a "zero based" cteTally) to just one 
          instance of one add and one instance of a subtract. The length calculation for the final element (not 
          followed by a delimiter) in the string to be split has been greatly simplified by using the ISNULL/NULLIF 
          combination to determine when the CHARINDEX returned a 0 which indicates there are no more delimiters to be
          had or to start with. Depending on the width of the elements, this code is between 4 and 8 times faster on a
          single CPU box than the original code especially near the 8K boundary.
        - Modified comments to include more sanity checks on the usage example, etc.
        - Removed "other" notes 8 and 9 as they were no longer applicable.

 Rev 06 - 12 Apr 2011 - Jeff Moden
        - Based on a suggestion by Ron "Bitbucket" McCullough, additional test rows were added to the sample code and
          the code was changed to encapsulate the output in pipes so that spaces and empty strings could be perceived 
          in the output.  The first "Notes" section was added.  Finally, an extra test was added to the comments above.

 Rev 07 - 06 May 2011 - Peter de Heer, a further 15-20% performance enhancement has been discovered and incorporated 
          into this code which also eliminated the need for a "zero" position in the cteTally table. 
**********************************************************************************************************************/
--===== Define I/O parameters
        (@pString VARCHAR(8000), @pDelimiter CHAR(1))
RETURNS TABLE WITH SCHEMABINDING AS
 RETURN
--===== "Inline" CTE Driven "Tally Table" produces values from 0 up to 10,000...
     -- enough to cover NVARCHAR(4000)
  WITH E1(N) AS (
                 SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL 
                 SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL 
                 SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1
                ),                          --10E+1 or 10 rows
       E2(N) AS (SELECT 1 FROM E1 a, E1 b), --10E+2 or 100 rows
       E4(N) AS (SELECT 1 FROM E2 a, E2 b), --10E+4 or 10,000 rows max
 cteTally(N) AS (--==== This provides the "base" CTE and limits the number of rows right up front
                     -- for both a performance gain and prevention of accidental "overruns"
                 SELECT TOP (ISNULL(DATALENGTH(@pString),0)) ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E4
                ),
cteStart(N1) AS (--==== This returns N+1 (starting position of each "element" just once for each delimiter)
                 SELECT 1 UNION ALL
                 SELECT t.N+1 FROM cteTally t WHERE SUBSTRING(@pString,t.N,1) = @pDelimiter
                ),
cteLen(N1,L1) AS(--==== Return start and length (for use in substring)
                 SELECT s.N1,
                        ISNULL(NULLIF(CHARINDEX(@pDelimiter,@pString,s.N1),0)-s.N1,8000)
                   FROM cteStart s
                )
--===== Do the actual split. The ISNULL/NULLIF combo handles the length for the final element when no delimiter is found.
 SELECT ItemNumber = ROW_NUMBER() OVER(ORDER BY l.N1),
        Item       = SUBSTRING(@pString, l.N1, l.L1)
   FROM cteLen l
;

GO

Answer 7

试试这个(改变''to','或你想要使用的分隔符的实例)

CREATE FUNCTION dbo.Wordparser
(
  @multiwordstring VARCHAR(255),
  @wordnumber      NUMERIC
)
returns VARCHAR(255)
AS
  BEGIN
      DECLARE @remainingstring VARCHAR(255)
      SET @remainingstring=@multiwordstring

      DECLARE @numberofwords NUMERIC
      SET @numberofwords=(LEN(@remainingstring) - LEN(REPLACE(@remainingstring, ' ', '')) + 1)

      DECLARE @word VARCHAR(50)
      DECLARE @parsedwords TABLE
      (
         line NUMERIC IDENTITY(1, 1),
         word VARCHAR(255)
      )

      WHILE @numberofwords > 1
        BEGIN
            SET @word=LEFT(@remainingstring, CHARINDEX(' ', @remainingstring) - 1)

            INSERT INTO @parsedwords(word)
            SELECT @word

            SET @remainingstring= REPLACE(@remainingstring, Concat(@word, ' '), '')
            SET @numberofwords=(LEN(@remainingstring) - LEN(REPLACE(@remainingstring, ' ', '')) + 1)

            IF @numberofwords = 1
              BREAK

            ELSE
              CONTINUE
        END

      IF @numberofwords = 1
        SELECT @word = @remainingstring
      INSERT INTO @parsedwords(word)
      SELECT @word

      RETURN
        (SELECT word
         FROM   @parsedwords
         WHERE  line = @wordnumber)

  END

用法示例:

SELECT dbo.Wordparser(COLUMN, 1),
       dbo.Wordparser(COLUMN, 2),
       dbo.Wordparser(COLUMN, 3)
FROM   TABLE

Answer 8

使用SQL Server 2016,我们可以使用string_split来完成此任务:

create table commasep (
 id int identity(1,1)
 ,string nvarchar(100) )

insert into commasep (string) values ('John, Adam'), ('test1,test2,test3')

select id, [value] as String from commasep 
 cross apply string_split(string,',')

Answer 9

我认为PARSENAME是用于此示例的简洁函数,如本文所述:http://www.sqlshack.com/parsing-and-rotating-delimited-data-in-sql-server-2012/

PARSENAME函数在逻辑上设计用于解析四部分对象名称.PARSENAME的优点在于它不仅仅解析SQL Server的四部分对象名称 - 它将解析由点分隔的任何函数或字符串数​​据.

第一个参数是要解析的对象,第二个参数是要返回的对象块的整数值.本文讨论解析和旋转分隔数据 - 公司电话号码,但它也可用于解析姓名/姓氏数据.

例:

USE COMPANY;
SELECT PARSENAME('Whatever.you.want.parsed',3) AS 'ReturnValue';

本文还介绍了使用名为"replaceChars"的公用表表达式(CTE)来对分隔符替换值运行PARSENAME.CTE对于返回临时视图或结果集很有用.

之后,UNPIVOT函数已用于将某些列转换为行; SUBSTRING和CHARINDEX函数已用于清除数据中的不一致性,最终使用了LAG函数(SQL Server 2012的新功能),因为它允许引用先前的记录.

Answer 10

我们可以创建一个函数

CREATE Function [dbo].[fn_CSVToTable] 
(
    @CSVList Varchar(max)
)
RETURNS @Table TABLE (ColumnData VARCHAR(100))
AS
BEGIN
    IF RIGHT(@CSVList, 1) <> ','
    SELECT @CSVList = @CSVList + ','

    DECLARE @Pos    BIGINT,
            @OldPos BIGINT
    SELECT  @Pos    = 1,
            @OldPos = 1

    WHILE   @Pos < LEN(@CSVList)
        BEGIN
            SELECT  @Pos = CHARINDEX(',', @CSVList, @OldPos)
            INSERT INTO @Table
            SELECT  LTRIM(RTRIM(SUBSTRING(@CSVList, @OldPos, @Pos - @OldPos))) Col001

            SELECT  @OldPos = @Pos + 1
        END

    RETURN
END

然后,我们可以使用SELECT语句将CSV值分隔到各自的列中

Answer 11

CREATE FUNCTION [dbo].[fn_split_string_to_column] (
    @string NVARCHAR(MAX),
    @delimiter CHAR(1)
    )
RETURNS @out_put TABLE (
    [column_id] INT IDENTITY(1, 1) NOT NULL,
    [value] NVARCHAR(MAX)
    )
AS
BEGIN
    DECLARE @value NVARCHAR(MAX),
        @pos INT = 0,
        @len INT = 0

    SET @string = CASE 
            WHEN RIGHT(@string, 1) != @delimiter
                THEN @string + @delimiter
            ELSE @string
            END

    WHILE CHARINDEX(@delimiter, @string, @pos + 1) > 0
    BEGIN
        SET @len = CHARINDEX(@delimiter, @string, @pos + 1) - @pos
        SET @value = SUBSTRING(@string, @pos, @len)

        INSERT INTO @out_put ([value])
        SELECT LTRIM(RTRIM(@value)) AS [column]

        SET @pos = CHARINDEX(@delimiter, @string, @pos + @len) + 1
    END

    RETURN
END

Answer 12

SELECT id,
       Substring(NAME, 0, Charindex(',', NAME))             AS firstname,
       Substring(NAME, Charindex(',', NAME), Len(NAME) + 1) AS lastname
FROM   spilt  

Answer 13

我认为以下功能对您有用:

您必须首先在SQL中创建一个函数.像这样

CREATE FUNCTION [dbo].[fn_split](
@str VARCHAR(MAX),
@delimiter CHAR(1)
)
RETURNS @returnTable TABLE (idx INT PRIMARY KEY IDENTITY, item VARCHAR(8000))
AS
BEGIN
DECLARE @pos INT
SELECT @str = @str + @delimiter
WHILE LEN(@str) > 0 
    BEGIN
        SELECT @pos = CHARINDEX(@delimiter,@str)
        IF @pos = 1
            INSERT @returnTable (item)
                VALUES (NULL)
        ELSE
            INSERT @returnTable (item)
                VALUES (SUBSTRING(@str, 1, @pos-1))
        SELECT @str = SUBSTRING(@str, @pos+1, LEN(@str)-@pos)       
    END
RETURN
END

您可以调用此函数,如下所示:

select * from fn_split('1,24,5',',')

执行:

Declare @test TABLE (
ID VARCHAR(200),
Data VARCHAR(200)
)

insert into @test 
(ID, Data)
Values
('1','Cleo,Smith')


insert into @test 
(ID, Data)
Values
('2','Paul,Grim')

select ID,
(select item from fn_split(Data,',') where idx in (1)) as Name ,
(select item from fn_split(Data,',') where idx in (2)) as Surname
 from @test

结果将是这样的:

Answer 14

使用Parsename()函数

with cte as(
    select 'Aria,Karimi' as FullName
    Union
    select 'Joe,Karimi' as FullName
    Union
    select 'Bab,Karimi' as FullName
)

SELECT PARSENAME(REPLACE(FullName,',','.'),2) as Name, 
       PARSENAME(REPLACE(FullName,',','.'),1) as Family
    FROM cte

结果

Name    Family
-----   ------
Aria    Karimi
Bab     Karimi
Joe     Karimi

Answer 15

您可以使用STRING_SPLIT仅在兼容性级别130下可用的内置函数。如果您的数据库兼容性级别低于130，则SQL Server将无法找到和执行STRING_SPLIT函数。您可以使用以下命令更改数据库的兼容性级别：

ALTER DATABASE DatabaseName SET COMPATIBILITY_LEVEL = 130

句法

STRING_SPLIT ( string , separator )

在这里查看文档

Answer 16

尝试这个：

declare @csv varchar(100) ='aaa,bb,csda,daass';
set @csv = @csv+',';

with cte as
(
    select SUBSTRING(@csv,1,charindex(',',@csv,1)-1) as val, SUBSTRING(@csv,charindex(',',@csv,1)+1,len(@csv)) as rem 
    UNION ALL
    select SUBSTRING(a.rem,1,charindex(',',a.rem,1)-1)as val, SUBSTRING(a.rem,charindex(',',a.rem,1)+1,len(A.rem)) 
    from cte a where LEN(a.rem)>=1
    ) select val from cte

Answer 17

这个函数是最快的：

CREATE FUNCTION dbo.F_ExtractSubString
(
  @String VARCHAR(MAX),
  @NroSubString INT,
  @Separator VARCHAR(5)
)
RETURNS VARCHAR(MAX) AS
BEGIN
    DECLARE @St INT = 0, @End INT = 0, @Ret VARCHAR(MAX)
    SET @String = @String + @Separator
    WHILE CHARINDEX(@Separator, @String, @End + 1) > 0 AND @NroSubString > 0
    BEGIN
        SET @St = @End + 1
        SET @End = CHARINDEX(@Separator, @String, @End + 1)
        SET @NroSubString = @NroSubString - 1
    END
    IF @NroSubString > 0
        SET @Ret = ''
    ELSE
        SET @Ret = SUBSTRING(@String, @St, @End - @St)
    RETURN @Ret
END
GO

用法示例：

SELECT dbo.F_ExtractSubString(COLUMN, 1, ', '),
       dbo.F_ExtractSubString(COLUMN, 2, ', '),
       dbo.F_ExtractSubString(COLUMN, 3, ', ')
FROM   TABLE

Answer 18

我遇到了类似的问题，但很复杂，因为这是我发现的有关该问题的第一个线索，所以我决定发表我的发现。我知道这是解决一个简单问题的复杂方法，但我希望我可以帮助其他寻求该复杂方法的人。我必须拆分一个包含5个数字的字符串（列名称：levelsFeed），并在单独的列中显示每个数字。例如：8,1,2,2,2应显示为：

1  2  3  4  5
-------------
8  1  2  2  2

解决方案1：使用XML函数：此解决方案是迄今为止最慢的解决方案

SELECT Distinct FeedbackID, 
, S.a.value('(/H/r)[1]', 'INT') AS level1
, S.a.value('(/H/r)[2]', 'INT') AS level2
, S.a.value('(/H/r)[3]', 'INT') AS level3
, S.a.value('(/H/r)[4]', 'INT') AS level4
, S.a.value('(/H/r)[5]', 'INT') AS level5
FROM (            
    SELECT *,CAST (N'<H><r>' + REPLACE(levelsFeed, ',', '</r><r>')  + '</r> </H>' AS XML) AS [vals]
    FROM Feedbacks 
)  as d
CROSS APPLY d.[vals].nodes('/H/r') S(a)

解决方案2：使用分割功能和旋转。（split函数将字符串拆分为具有列名称Data的行）

SELECT FeedbackID, [1],[2],[3],[4],[5]
FROM (
    SELECT *, ROW_NUMBER() OVER (PARTITION BY feedbackID ORDER BY (SELECT  null)) as rn 
FROM (
    SELECT FeedbackID, levelsFeed
    FROM Feedbacks 
) as a
CROSS APPLY dbo.Split(levelsFeed, ',')
) as SourceTable
PIVOT
(
    MAX(data)
    FOR rn IN ([1],[2],[3],[4],[5])
)as pivotTable

解决方案3：使用字符串操作功能-比解决方案2快一点

SELECT FeedbackID,
SUBSTRING(levelsFeed,0,CHARINDEX(',',levelsFeed)) AS level1,
PARSENAME(REPLACE(SUBSTRING(levelsFeed,CHARINDEX(',',levelsFeed)+1,LEN(levelsFeed)),',','.'),4) AS level2,
PARSENAME(REPLACE(SUBSTRING(levelsFeed,CHARINDEX(',',levelsFeed)+1,LEN(levelsFeed)),',','.'),3) AS level3,
PARSENAME(REPLACE(SUBSTRING(levelsFeed,CHARINDEX(',',levelsFeed)+1,LEN(levelsFeed)),',','.'),2) AS level4,
PARSENAME(REPLACE(SUBSTRING(levelsFeed,CHARINDEX(',',levelsFeed)+1,LEN(levelsFeed)),',','.'),1) AS level5
FROM Feedbacks

由于levelsFeed包含5个字符串值，因此我需要为第一个字符串使用子字符串功能。

我希望我的解决方案可以帮助其他人找到更复杂的拆分为列方法

Answer 19

使用instring函数:)

select Value, 
       substring(String,1,instr(String," ") -1) Fname,  
       substring(String,instr(String,",") +1) Sname 
from tablename;

使用了两个函数,
1.substring(string, position, length) ==>从positon返回字符串到长度
2.instr(string,pattern) ==>返回模式的位置.

如果我们不在子字符串中提供长度参数,则返回直到字符串结尾