Question

我有这样的文字

localStorage = undefined;

第二个例子是

Key:Value
Key2:Value2
Key3:Value3

i have
a very 
long
uncommom
text which i need to drop

Key4:Valu4

重点是删除句子

Key:Value
Key2:Value2
Key3:Value3
i have a very long uncommom text which i need to drop

Key4:Valu4

这两个SQL字符串中的

。我需要在其中包含i have a very long uncommom text which i need to drop和CHAR(10)中提及。

我需要在key：value对上保留新行。

如何实现？

这行不通。

CHAR(13)

编辑：还有没有办法用一个替换双/三/四新换行符？

Answer 1

以下代码演示了一种将字符串拆分为单独的行并重新组装包含冒号的行的方法。它保持输入行的顺序，并且不需要任何最新功能，例如String_Split。

-- Sample data.
declare @Newline as VarChar(2) = Char(10) + Char(13);
declare @Sample as VarChar(1024) =
  'Key:Value' + @Newline +
  'Key2:Value2' + @Newline +
  'Key3:Value3' + @Newline +
  @Newline +
  'i have' + @Newline +
  'a very ' + @Newline +
  'long ' + @Newline +
  'uncommom' + @Newline +
  'text which i need to drop' + @Newline +
  @Newline +
  'Key4:Valu4';

-- Display the sample data.
select @Sample as Sample, Replace( @Sample, @Newline, '¶' ) as VisibleSample;

-- Test the splitter.
select ItemNumber, Item, Replace( Item, @Newline, '¶' ) as VisibleItem
  from dbo.DelimitedSplit8K( @Sample, @Newline )
  where Item like '%:%';

-- Reassemble the items that include a colon.
declare @Result as NVarChar(1024) = Stuff(
  ( select @Newline + Item
      from dbo.DelimitedSplit8K( @Sample, @Newline )
      where Item like '%:%'
      order by ItemNumber for XML path(''), type).value('.[1]', 'VarChar(max)' ),
    1, Len( @NewLine ), '' );
select @Result as Result, Replace( @Result, @Newline, '¶' ) as VisibleResult;

分离器是Jeff Moden's代码的修改版本，可处理可变长度定界符：

CREATE FUNCTION [dbo].[DelimitedSplit8K]
--===== Define I/O parameters
        (@pString VARCHAR(8000), @pDelimiter VARCHAR(16))
--WARNING!!! DO NOT USE MAX DATA-TYPES HERE!  IT WILL KILL PERFORMANCE!
RETURNS TABLE WITH SCHEMABINDING AS
 RETURN
--===== "Inline" CTE Driven "Tally Table" produces values from 1 up to 10,000...
     -- enough to cover VARCHAR(8000)
  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+ Len( @pDelimiter ) FROM cteTally t WHERE SUBSTRING(@pString,t.N, Len( @pDelimiter ) ) = @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
;

Answer 2

这应该有效：

declare @string nvarchar(max) = 
'Key:Value
Key2:Value2
Key3:Value3
i have a very 
long uncommom text which i need to drop

Key4:Valu4'

DECLARE @Str NVARCHAR(MAX);
DECLARE @Result NVARCHAR(MAX)='';

--This is just for test the cursor query
SELECT REPLACE(REPLACE(value, CHAR(13), ''), CHAR(10), '') 
FROM STRING_SPLIT(@string, CHAR(13))
WHERE CHARINDEX(':', value) != 0

DECLARE db_cursor CURSOR FOR 
    SELECT REPLACE(REPLACE(value, CHAR(13), ''), CHAR(10), '') 
    FROM STRING_SPLIT(@string, CHAR(13))
    WHERE CHARINDEX(':', value) != 0

OPEN db_cursor  
FETCH NEXT FROM db_cursor INTO @Str  

WHILE @@FETCH_STATUS = 0  
BEGIN  
      SET @Result += @Str + CHAR(13) + CHAR(10); 

      FETCH NEXT FROM db_cursor INTO @Str 
END 

CLOSE db_cursor  
DEALLOCATE db_cursor

SELECT @Result

查询使用“ STRING_SPLIT”函数单独到达每一行，然后根据现有的“：”字符决定是否保留该行。最后，游标循环创建所有有效行（键/值）的附加行。

字符串替换字符串的特定部分

2 个答案: