Sql server 2008 传入的大列表上的sql server 2008筛选器

我有一个性能问题。我试图根据一个很长的参数列表从表中进行选择

当前我正在使用这个存储过程

CREATE PROC [dbo].[GetFileContentsFromTitles]
@MyTitles varchar(max)
AS
SELECT [Title], [Sequence] From [dbo].[MasterSequence]
WHERE charindex(',' + Title + ',', ',' + @MyTitles + ',') > 0;

---

其中@MyTitles可能是一个非常大的数字（目前使用的字符串中有4000个条目，以逗号分隔）。有什么建议吗？谢谢

好的，如果你想要这样的东西的性能，那么你需要使用最好的东西。首先，创建用于拆分字符串的函数（大约两周前我从Jeff Moden那里得到）：

是的，它很长，但这主要是解释它和它的历史的评论。别担心，它是t-SQL中可用的最快的东西（只有AFAIK的SQLCLR更快，而这不是t-SQL）

请注意，它最多只支持VARCHAR（8000）。如果您真的需要VARCHAR（MAX），那么可以很容易地将其更改为VARCHAR（MAX），但是VARCHAR（MAX）的速度大约是VARCHAR（MAX）的两倍

现在，您可以执行以下步骤：

CREATE PROC [dbo].[GetFileContentsFromTitles]
@MyTitles varchar(max)
AS
SELECT *
INTO #tmpTitles
FROM dbo.DelimitedSplit8K(@MyTitles, ',')

SELECT [Title], [Sequence] From [dbo].[MasterSequence]
WHERE Title IN (SELECT item FROM #tmpTitles)

如果没有DDL和一些数据，我无法为您测试这个，但它应该快得多。如果没有，那么我们可能需要在temp表中的[item]列上抛出一个索引

---

下面是使用VARCHAR（MAX）的拆分函数的另一个版本：

---

但是，请预先警告，我只将其设置为最多100000000个字符。另外，我还没有机会测试它，你应该确保自己测试它。

是的，这看起来像是我从另一个问题上的把戏。它可以工作，但速度不快，因为它不能使用标题列中的任何索引。在一张大桌子上，速度会非常慢。就像一个符咒一样，很遗憾，我不得不使用MAX，因为我们处理的是大量的收藏品。除了Varchar（MAX）之外，还有什么变化吗？理货台也必须扩展。我把它增加到100000000个字符，所以如果你可能有比这更大的字符串，它将需要一些调整。

CREATE PROC [dbo].[GetFileContentsFromTitles]
@MyTitles varchar(max)
AS
SELECT *
INTO #tmpTitles
FROM dbo.DelimitedSplit8K(@MyTitles, ',')

SELECT [Title], [Sequence] From [dbo].[MasterSequence]
WHERE Title IN (SELECT item FROM #tmpTitles)

 ALTER FUNCTION [dbo].[DelimitedSplitMax]
/**********************************************************************************************************************
 Purpose:
 Split a given string at a given delimiter and return a list of the split elements (items).

 Notes:
 1.  Leading a trailing delimiters are treated as if an empty string element were present.
 2.  Consecutive delimiters are treated as if an empty string element were present between them.
 3.  Except when spaces are used as a delimiter, all spaces present in each element are preserved.

 Returns:
 iTVF containing the following:
 ItemNumber = Element position of Item as a BIGINT (not converted to INT to eliminate a CAST)
 Item       = Element value as a VARCHAR(MAX)

 Statistics on this function may be found at the following URL:
 http://www.sqlservercentral.com/Forums/Topic1101315-203-4.aspx

-----------------------------------------------------------------------------------------------------------------------
 Other Notes:
 1. Optimized for VARCHAR(8000) or less.  No testing or error reporting for truncation at 8000 characters is done.
 2. Optimized for single character delimiter.  Multi-character delimiters should be resolvedexternally from this 
    function.
 3. Optimized for use with CROSS APPLY.
 4. Does not "trim" elements just in case leading or trailing blanks are intended.
 5. If you don't know how a Tally table can be used to replace loops, please see the following...
    http://www.sqlservercentral.com/articles/T-SQL/62867/
 6. Changing this function to use NVARCHAR(MAX) will cause it to run twice as slow.  It's just the nature of 
    VARCHAR(MAX) whether it fits in-row or not.
 7. Multi-machine testing for the method of using UNPIVOT instead of 10 SELECT/UNION ALLs shows that the UNPIVOT method
    is quite machine dependent and can slow things down quite a bit.
-----------------------------------------------------------------------------------------------------------------------
 Credits:
 This code is the product of many people's efforts including but not limited to the following:
 cteTally concept originally by Iztek Ben Gan and "decimalized" by Lynn Pettis (and others) for a bit of extra speed
 and finally redacted by Jeff Moden for a different slant on readability and compactness. Hat's off to Paul White for
 his simple explanations of CROSS APPLY and for his detailed testing efforts. Last but not least, thanks to
 Ron "BitBucket" McCullough and Wayne Sheffield for their extreme performance testing across multiple machines and
 versions of SQL Server.  The latest improvement brought an additional 15-20% improvement over Rev 05.  Special thanks
 to "Nadrek" and "peter-757102" (aka Peter de Heer) for bringing such improvements to light.  Nadrek's original
 improvement brought about a 10% performance gain and Peter followed that up with the content of Rev 07.  

 I also thank whoever wrote the first article I ever saw on "numbers tables" which is located at the following URL
 and to Adam Machanic for leading me to it many years ago.
 http://sqlserver2000.databases.aspfaq.com/why-should-i-consider-using-an-auxiliary-numbers-table.html
-----------------------------------------------------------------------------------------------------------------------
 Revision History:
 Rev 00 - 20 Jan 2010 - Concept for inline cteTally: Lynn Pettis and others.
                        Redaction/Implementation: Jeff Moden 
        - Base 10 redaction and reduction for CTE.  (Total rewrite)

 Rev 01 - 13 Mar 2010 - Jeff Moden
        - Removed one additional concatenation and one subtraction from the SUBSTRING in the SELECT List for that tiny
          bit of extra speed.

 Rev 02 - 14 Apr 2010 - Jeff Moden
        - No code changes.  Added CROSS APPLY usage example to the header, some additional credits, and extra 
          documentation.

 Rev 03 - 18 Apr 2010 - Jeff Moden
        - No code changes.  Added notes 7, 8, and 9 about certain "optimizations" that don't actually work for this
          type of function.

 Rev 04 - 29 Jun 2010 - Jeff Moden
        - Added WITH SCHEMABINDING thanks to a note by Paul White.  This prevents an unnecessary "Table Spool" when the
          function is used in an UPDATE statement even though the function makes no external references.

 Rev 05 - 02 Apr 2011 - Jeff Moden
        - Rewritten for extreme performance improvement especially for larger strings approaching the 8K boundary and
          for strings that have wider elements.  The redaction of this code involved removing ALL concatenation of 
          delimiters, optimization of the maximum "N" value by using TOP instead of including it in the WHERE clause,
          and the reduction of all previous calculations (thanks to the switch to a "zero based" cteTally) to just one 
          instance of one add and one instance of a subtract. The length calculation for the final element (not 
          followed by a delimiter) in the string to be split has been greatly simplified by using the ISNULL/NULLIF 
          combination to determine when the CHARINDEX returned a 0 which indicates there are no more delimiters to be
          had or to start with. Depending on the width of the elements, this code is between 4 and 8 times faster on a
          single CPU box than the original code especially near the 8K boundary.
        - Modified comments to include more sanity checks on the usage example, etc.
        - Removed "other" notes 8 and 9 as they were no longer applicable.

 Rev 06 - 12 Apr 2011 - Jeff Moden
        - Based on a suggestion by Ron "Bitbucket" McCullough, additional test rows were added to the sample code and
          the code was changed to encapsulate the output in pipes so that spaces and empty strings could be perceived 
          in the output.  The first "Notes" section was added.  Finally, an extra test was added to the comments above.

 Rev 07 - 06 May 2011 - Peter de Heer, a further 15-20% performance enhancement has been discovered and incorporated 
          into this code which also eliminated the need for a "zero" position in the cteTally table. 

 Rev 07a- 18 Oct 2012 - RBarryYoung, Varchar(MAX), because its needed, even though its slower...
**********************************************************************************************************************/
--===== Define I/O parameters
        (@pString VARCHAR(MAX), @pDelimiter CHAR(1))
RETURNS TABLE WITH SCHEMABINDING AS
 RETURN
--===== "Inline" CTE Driven "Tally Table" produces values from 1 up to 100,000,000...
     -- hopefully enough to cover most VARCHAR(MAX)'s
  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
       E8(N) AS (SELECT 1 FROM E4 a, E4 b), --10E+8 or 100,000,000 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 E8
                ),
cteStart(N1) AS (--==== This returns N+1 (starting position of each "element" just once for each delimiter)
                 SELECT 1 UNION ALL
                 SELECT t.N+1 FROM cteTally t WHERE SUBSTRING(@pString,t.N,1) = @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.N1,999999999)
                   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
;