SQL Server 2012 逗号解析

Question

我正在尝试从 SQL Server 2012 的列中解析一些逗号分隔值，同时仍保留左侧和右侧列中的数据。

我见过一些类似的主题解决方案，但似乎都不是我想要的。

我有这个：

FirstName   LastName    userid   Regions          ViewCosts HelpReviewCosts
---------------------------------------------------------------------
Darron      Peters      ya00003   All                y         y
John        Davies      ya30982   NA, EM, AP, LA     n         n

我正在尝试解析 Regions 列，以便得到这个：

FirstName   LastName    userid   Regions          ViewCosts HelpReviewCosts
---------------------------------------------------------------------
Darron      Peters      ya00003   All                y         y
John        Davies      ya30982   NA                 n         n
John        Davies      ya30982   EM                 n         n
John        Davies      ya30982   AP                 n         n
John        Davies      ya30982   LA                 n         n

Answer 1

关于如何拆分/解析字符串的示例有数千个。下面是两个示例，一个带有 UDF，另一个没有。两者都使用 CROSS APPLY

使用 UDF

Declare @Yourtable table (FirstName varchar(25)   ,LastName varchar(25),userid  varchar(25),  Regions varchar(50), ViewCosts varchar(25), HelpReviewCosts varchar(25))
Insert Into @Yourtable values
('Darron','Peters','ya00003','All','y','y'),
('John','Davies','ya30982','NA, EM, AP, LA','n','n')

Select A.FirstName
      ,A.LastName    
      ,A.userid   
      ,Regions =B.RetVal
      ,A.ViewCosts 
      ,A.HelpReviewCosts
 From @Yourtable A
 Cross Apply [dbo].[udf-Str-Parse](A.Regions,',') B

没有 UDF

Select A.FirstName
      ,A.LastName    
      ,A.userid   
      ,Regions =B.RetVal
      ,A.ViewCosts 
      ,A.HelpReviewCosts
 From @Yourtable A
 Cross Apply ( 
                Select RetSeq = Row_Number() over (Order By (Select null))
                      ,RetVal = LTrim(RTrim(B.i.value('(./text())[1]', 'varchar(max)')))
                From  (Select x = Cast('<x>'+ replace((Select A.Regions as [*] For XML Path('')),',','</x><x>')+'</x>' as xml).query('.')) as A 
                Cross Apply x.nodes('x') AS B(i)
      ) B

两个回报

UDF（如果需要）

CREATE FUNCTION [dbo].[udf-Str-Parse] (@String varchar(max),@Delimiter varchar(10))
Returns Table 
As
Return (  
    Select RetSeq = Row_Number() over (Order By (Select null))
          ,RetVal = LTrim(RTrim(B.i.value('(./text())[1]', 'varchar(max)')))
    From  (Select x = Cast('<x>'+ replace((Select @String as [*] For XML Path('')),@Delimiter,'</x><x>')+'</x>' as xml).query('.')) as A 
    Cross Apply x.nodes('x') AS B(i)
);
--Select * from [dbo].[udf-Str-Parse]('Dog,Cat,House,Car',',')
--Select * from [dbo].[udf-Str-Parse]('John Cappelletti was here',' ')
--Select * from [dbo].[udf-Str-Parse]('this,is,<test>,for,< & >',',')

Answer 2

我建议你使用 STRING_SPLIT 函数

WITH 
CTE_Sample AS
(
    SELECT 'All'            AS txt
    UNION ALL
    SELECT 'NA, EM, AP, LA' AS txt
)

SELECT
    txt,
    value
  FROM CTE_Sample
  CROSS APPLY STRING_SPLIT(txt, ','); 

Answer 3

如果你不想'udf'和'string_split'函数，那么你可以使用这个查询。它适用于逗号分隔的大字符串，也比其他的快得多......

`CREATE TABLE TB (Number INT)
 DECLARE @I INT=0
 WHILE @I<1000
 BEGIN
 INSERT INTO TB VALUES (@I)
 SET @I=@I+1
 END
 SELECT 
    FirstName
    ,LastName
    ,userid
    ,S_DATA
    ,ViewCosts
    ,HelpReviewCosts
FROM    (
    SELECT
            FirstName
            ,LastName
            ,userid
            ,CASE   WHEN LEN(LIST2)>0 THEN LTRIM(RTRIM(SUBSTRING(LIST2, NUMBER+1, CHARINDEX(',', LIST2, NUMBER+1)-NUMBER - 1)))
                    ELSE NULL
            END AS S_DATA 
            ,ViewCosts
            ,HelpReviewCosts
           ,NUMBER
    FROM(
        SELECT  FirstName
                ,LastName
                ,userid
                ,','+Regions+',' LIST2
                ,ViewCosts
                ,HelpReviewCosts
                FROM Tb1
        )DT 
         LEFT OUTER JOIN TB N ON (N.NUMBER < LEN(DT.LIST2)) OR (N.NUMBER=1 AND DT.LIST2 IS NULL)
        WHERE SUBSTRING(LIST2, NUMBER, 1) = ',' OR LIST2 IS NULL
     ) DT2
     WHERE S_DATA<>''

this is my Output