Question

我有一个拆分分隔列表的视图。例如，如果您的下表包含以下两列：

ABC, A;B;C

假设名称为“TestView”，您将获得以下内容：

Label  Source
--------------
ABC    A
ABC    B
ABC    C

代码源自此处：Split one column into multiple rows

当我尝试在视图的where子句中放入一个条件时，我收到一个错误。 “传递给LEFT或SUBSTRING函数的长度参数无效。”所以任何类似“从TestView中选择*来源='A'”都会导致错误。

以下是视图中的代码：

CREATE VIEW [dbo].[TestView]
AS
WITH L0 AS (SELECT 1 AS c 
            UNION ALL 
            SELECT 1),
     L1 AS (SELECT 1 AS c 
               FROM L0 AS A, 
                    L0 AS B),
     L2 AS (SELECT 1 AS c 
              FROM L1 AS A, 
                   L1 AS B),
     L3 AS (SELECT 1 AS c 
              FROM L2 AS A, 
                   L2 AS B),
     --counts up to 256
     Numbers AS (SELECT ROW_NUMBER() OVER (ORDER BY c) AS n 
                   FROM L3)
SELECT Label,        
       LTRIM(RTRIM(SUBSTRING(valueTable.Sources, nums.n, charindex(N';', valueTable.Sources + N';', nums.n) - nums.n))) AS Source
  FROM Numbers AS nums 
  JOIN dbo.SourceTable AS valueTable ON nums.n <= CONVERT(int, LEN(valueTable.Sources)) 
                                    AND SUBSTRING(N';' + valueTable.Sources, n, 1) = N';'

Answer 1

无效长度参数通常意味着您将负值传递给子字符串函数。

找出每件唱片的结果： charindex（N';'，valueTable.Sources + N';'，nums.n） - nums.n

我敢打赌，charindex返回0表示找不到该值，nums.n大于0。

Answer 2

该链接提供了另一篇文章（http://www.sqlservercentral.com/articles/Tally+Table/72993/）的链接，该文章提供了一个非常高性能的分割器功能。

您可以尝试使用此

CREATE FUNCTION dbo.DelimitedSplit8K
--===== 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 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 "zero base" and limits the number of rows right up front
                 -- for both a performance gain and prevention of accidental "overruns"
             SELECT 0 UNION ALL
             SELECT TOP (DATALENGTH(ISNULL(@pString,1))) 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 t.N+1
               FROM cteTally t
              WHERE (SUBSTRING(@pString,t.N,1) = @pDelimiter OR t.N = 0) 
            )
--===== 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 s.N1),
    Item       =    SUBSTRING(@pString,s.N1,ISNULL(NULLIF(CHARINDEX(@pDelimiter,@pString,s.N1),0)-s.N1,8000))
   FROM cteStart s
;

然后就是

的情况

with rawData (Label,rawString) as (select 'ABC','A;B;C')

select Label,Item From rawData
Cross Apply DelimitedSplit8K(rawData.rawString, ';')
WHERE Item = 'A'

Where子句标准在视图上导致错误

2 个答案: