当 where 子句与 table 值函数一起使用时会发生错误？

Question

我有以下 table 值的 UDF：

CREATE FUNCTION [dbo].[funParseRestParams](
    @Params NVARCHAR(MAX),
    @Delim VARCHAR(100))
    RETURNS TABLE
    AS

        RETURN (
            SELECT 
                LTRIM(RTRIM(SUBSTRING([Argument], 1, CHARINDEX('=', [Argument], 1) - 1))) Parameter,
                LTRIM(RTRIM(SUBSTRING([Argument], CHARINDEX('=', [Argument], 1) + 1, LEN([Argument]) - CHARINDEX('=', [Argument], 1)))) Value
            FROM (          
                SELECT 
                    LTRIM(RTRIM(SUBSTRING(@Params, [Number], CHARINDEX(@Delim, @Params + @Delim, [Number]) - [Number]))) [Argument]
                FROM (
                    SELECT 
                        ROW_NUMBER() OVER (ORDER BY name) [Number]
                    FROM sys.all_objects) AS x
                WHERE Number <= LEN(@Params) AND SUBSTRING(@Delim + @Params, [Number], LEN(@Delim)) = @Delim) AS y);

GO

我正在运行使用来自 ReportServer.dbo.ExecutionLogStorage 的参数字符串在游标中进行此操作。参数看起来像这样："Some%20Param%20Name=Hello&Some%20Other%20Param=NoLuck"

当我运行游标中的函数是这样的：

SELECT * FROM Reports.dbo.funParseRestParams(@Param, '&')

一切都很好，但是当我添加一个 where 子句时：

    SELECT * FROM Reports.dbo.funParseRestParams(@Param, '&') R 
    WHERE R.[Parameter] = 'AccessType'

我每次都收到以下错误消息：

Msg 537, Level 16, State 3, Line 13
Invalid length parameter passed to the LEFT or SUBSTRING function.

那么为什么我的 where 子句会终止函数？

编辑：添加一些额外的东西。您可以将下面的代码粘贴到 SQL 服务器以复制此错误。该错误仅在使用 "first" 列（where 子句中的参数列）时发生。在 where 子句中使用 "second" 值列不会导致错误。您可以删除下面的评论以查看实际效果：

DECLARE @Params NVARCHAR(MAX)
DECLARE @Delim VARCHAR(1)

SET @Params = 'Greeting=Hello&Name=George&Dessert=Jello'
SET @Delim = '&'

SELECT * FROM (
    SELECT 
        LTRIM(RTRIM(SUBSTRING([Argument], 1, CHARINDEX('=', [Argument], 1) - 1))) Parameter,
        LTRIM(RTRIM(SUBSTRING([Argument], CHARINDEX('=', [Argument], 1) + 1, LEN([Argument]) - CHARINDEX('=', [Argument], 1)))) Value
    FROM (          
        SELECT 
            LTRIM(RTRIM(SUBSTRING(@Params, [Number], CHARINDEX(@Delim, @Params + @Delim, [Number]) - [Number]))) [Argument]
        FROM (
            SELECT 
                ROW_NUMBER() OVER (ORDER BY name) [Number]
            FROM sys.all_objects) AS x
        WHERE [Number] <= LEN(@Params) AND SUBSTRING(@Delim + @Params, [Number], LEN(@Delim)) = @Delim) AS y
) R 
--WHERE R.Parameter = 'AccessType'
--WHERE R.Parameter = 'Greeting'
--WHERE R.Value = 'Bananas'
--WHERE R.Value = 'Jello'

Answer 1

您不妨考虑以下内容：

CREATE FUNCTION dbo.SplitStrings_Moden
(
   @List NVARCHAR(MAX),
   @Delimiter NVARCHAR(255)
)
RETURNS TABLE
WITH SCHEMABINDING AS
RETURN
  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),
       E2(N)        AS (SELECT 1 FROM E1 a, E1 b),
       E4(N)        AS (SELECT 1 FROM E2 a, E2 b),
       E42(N)       AS (SELECT 1 FROM E4 a, E2 b),
       cteTally(N)  AS (SELECT 0 UNION ALL SELECT TOP (DATALENGTH(ISNULL(@List,1))) 
                         ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E42),
       cteStart(N1) AS (SELECT t.N+1 FROM cteTally t
                         WHERE (SUBSTRING(@List,t.N,1) = @Delimiter OR t.N = 0))
  SELECT Item = SUBSTRING(@List, s.N1, ISNULL(NULLIF(CHARINDEX(@Delimiter,@List,s.N1),0)-s.N1,8000))
    FROM cteStart s;

此代码归功于 Jeff Moden here。该站点还有其他方法。可能值得采用经过充分审查的解决方案（您也必须自己审查），而不是试图重新发明轮子并且不得不花费过多的时间来调试它。

Answer 2

我访问了 MSDN 以搜索答案，我得到了一个。我仍在查看细节，但出于某种原因，以下作品在原始作品中没有。第一个子查询的第二行被改变：

DECLARE @Params NVARCHAR(MAX)
DECLARE @Delim VARCHAR(1)

SET @Params = 'Greeting=Hello&Name=George&Dessert=Jello'
SET @Delim = '&'

SELECT * FROM (
    SELECT 
        LTRIM(RTRIM(SUBSTRING([Argument], 0, CHARINDEX('=', [Argument], 1) ))) Parameter,
        LTRIM(RTRIM(SUBSTRING([Argument], CHARINDEX('=', [Argument], 1) + 1, LEN([Argument]) - CHARINDEX('=', [Argument], 1)))) Value
    FROM (          
        SELECT 
            LTRIM(RTRIM(SUBSTRING(@Params, [Number], CHARINDEX(@Delim, @Params + @Delim, [Number]) - [Number]))) [Argument]
        FROM (
            SELECT 
                ROW_NUMBER() OVER (ORDER BY name) [Number]
            FROM sys.all_objects) AS x
        WHERE [Number] <= LEN(@Params) AND SUBSTRING(@Delim + @Params, [Number], LEN(@Delim)) = @Delim) AS y
) R 

--WHERE R.Parameter = 'AccessType'
WHERE R.Parameter = 'Greeting'
--WHERE R.Value = 'Bananas'
--WHERE R.Value = 'Jello'

当 where 子句与 table 值函数一起使用时会发生错误？

Error occurs when a where clause is used with a table valued function?

sql

sql-server

user-defined-functions