Sql Where子句关于导致错误的视图的标准

我有一个视图，它将分隔列表。例如，如果下表包含以下两列：

ABC, A;B;C

假设名称为TestView，您将得到以下结果：

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

代码从这里派生：

当我试图在视图的where子句中添加一个条件时，我得到了一个错误。传递给LEFT或SUBSTRING函数的长度参数无效。因此，任何类似于从TestView中选择*，其中Source='A'都会导致该错误

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';'

---

无效的长度参数通常意味着将负值传递给子字符串函数

找出每一条记录的结果： charindexN'；'，valueTable.Sources+N'；'，nums.n-nums.n

---

我敢打赌charindex返回的是一个0，表示它找不到该值，并且nums.n大于0。

该链接提供了指向另一篇文章的链接，该文章提供了一个性能相当好的拆分器功能

你可以试着用这个来代替

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
;

那么这将是一个

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

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

---

主表中有一个条目不包含值。谢谢你帮我找到了正确的线索。我会回去报告的。这篇文章的长度有些问题。但是我仍然不明白为什么它可以生成视图，但是它在where子句中失败了。但是，当我运行您发布的测试用例时，我在“.”附近得到了错误语法。好的，我已经解决了。兼容性级别需要从80提高到90。