Question

我有什么似乎是腐败指数？

以下是发生的事情。我有两个表函数，第一个是一组案例，第二个是一组有意识的日期。这两组具有1（案例）到0或1（知悉日期）关系。通常我会查询它们;

SELECT c.CaseID, a.AwareDate  
FROM Cases(@date) AS c  
LEFT JOIN AwareDates(@date) AS a ON c.CaseID = a.CaseID;

麻烦的是，AwareDates中所有匹配的行似乎都不是JOIN。如果我添加一个连接提示，他们就会这样做。说;

SELECT c.CaseID, a.AwareDate  
FROM Cases(@date) AS c  
LEFT MERGE JOIN AwareDates(@date) AS a ON c.CaseID = a.CaseID;

我从查询计划中注意到，添加连接提示会在连接之前添加一种AwareDate数据，否则就不存在。此外，当没有提示时，查询计划器将连接翻转到RIGHT OUTER JOIN，当然保持LEFT JOIN存在提示的位置。

我没有检测到任何错误，我已完成以下操作;

DBCC UPDATEUSAGE (0) WITH INFO_MESSAGES, COUNT_ROWS;  
EXECUTE sp_updatestats 'resample';  
DBCC CHECKDB (0) WITH ALL_ERRORMSGS, EXTENDED_LOGICAL_CHECKS;

我很难过......有什么想法吗？

以下是UDF定义

ALTER FUNCTION dbo.Cases( @day date ) RETURNS TABLE
WITH SCHEMABINDING
AS RETURN (
SELECT 
    CaseID -- other 42 columns ommitted
FROM (
    SELECT
        ROW_NUMBER() OVER (PARTITION BY CaseID ORDER BY UpdateDate DESC, UpdateNumber DESC) AS RecordAge,
        CaseID, 
        Action
    FROM
        dbo.CaseAudit
    WHERE
        convert(date,UpdateDate) <= @day
    ) AS History
WHERE
    RecordAge = 1                    -- only the most current record version
    AND isnull(Action,'') != N'DEL'  -- only include cases that have not been deleted
)

ALTER FUNCTION dbo.AwareDates( @day date ) RETURNS TABLE
WITH SCHEMABINDING
AS RETURN (
WITH 
    History AS (
        SELECT row_number() OVER (PARTITION BY CaseID, ContactID ORDER BY UpdateDate DESC, UpdateNumber DESC) AS RecordAge,
            CaseID, InfoReceived, ReceiveDate, ResetClock, Action
        FROM dbo.ContactLogAudit WITH (NOLOCK)
        WHERE convert(date,UpdateDate) <= @day
        ),
    Notes AS (
        SELECT 
            CaseID,
            convert(date,ReceiveDate,112) AS ReceiveDate,
            ResetClock
        FROM History 
        WHERE RecordAge = 1                -- only the most current record version
        AND isnull(Action,'') != N'DEL'    -- only include notes that have not been deleted
        AND InfoReceived = N'Y'            -- only include notes that have Info Rec'd checked 
        AND len(ReceiveDate) = 8 AND isnumeric(ReceiveDate) = 1 AND isdate(ReceiveDate) = 1 -- only include those with a valid aware date
        ),
    Initials AS (
        SELECT CaseID, min(ReceiveDate) AS ReceiveDate
        FROM Notes 
        GROUP BY CaseID
        ),
    Resets AS (
        SELECT CaseID, max(ReceiveDate) AS ReceiveDate
        FROM Notes 
        WHERE ResetClock = N'Y'
        GROUP BY CaseID
        )
SELECT 
    i.CaseID                              AS CaseID,
    i.ReceiveDate                         AS InitialAwareDate, -- the oldest valid aware date value (must have AE Info Reveived checked and a received date)
    coalesce(r.ReceiveDate,i.ReceiveDate) AS AwareDate  -- either the newest valid aware date value with the Reset Clock checked, otherwise the initial aware date value
FROM Initials AS i
LEFT JOIN Resets AS r 
    ON i.CaseID = r.CaseID
);

我进一步发现，如果我删除“WITH（NOLOCK）”表提示，我会得到正确的结果。此外，如果向AwareDates UTF添加连接提示，或者甚至在Initials和Resets之间的LEFT JOIN关系上添加COLLATE Latin1_General_BIN。

查询计划行数 - 没有连接提示（已损坏）

案件{实际：25,891，估计：19,071.9}
AwareDates {Actual：24,693，估计：1,463.09}
- 姓名缩写{实际：24,693，估计：1,463.09}
- 休息{实际：985，估计：33.2671}
AwareDates匹配join'd result-set

查询计划行数 - 使用加入提示（工作）

案件{实际：25,891，估计：19,071.9}
AwareDates {Actual：24,673，估计：1,837.67}
- 姓名首字母{实际：24,673，估计：1,837.67}
- 休息{实际：982，估计：42.6238}
AwareDates匹配join'd result-set

我进一步削弱了问题的范围。我可以;

SELECT * FROM AwareDate(@date);

和

SELECT * FROM AwareDate(@date) ORDER BY CaseID;

具有不同的行数。

Answer 1

您没有指定SQL的特定版本（@@ version），但这似乎与SQL 2008 R2的累积更新6中的bug that was fixed一样可疑（显然它也适用于SQL 2008）。

<强> KB 2433265
FIX：您运行使用该查询的查询时可能会收到不正确的结果 ROW_NUMBER函数与SQL Server 2008中的左外连接一起使用

本文中的示例指定了DISTINCT。然而，这篇文章措辞含糊不清 - 目前尚不清楚你是否需要一个独特的或者如果DISTINCT是其中一个触发器。

您的示例与文章没有明显区别，但为了提出问题（即缺少42列），它似乎已被修改。有明显的吗？同样在AwareDates udf中，当我进入Initials CTE时，你会做一个GROUP BY，它可以和DISTINCT具有相同的效果。

<强>更新

@Dennis从您的评论我仍然无法判断您是使用SQL 20080还是2008 R2。

如果您正在运行2008，知识库文章说“此问题的修复程序首先在SQL Server 2008 Service Pack 1的累积更新11中发布。”所以，发布SP1。

另一方面，如果你正在使用SQL 2008 R2，那么你在CU 6中修复了这是正确的，它是SP1的一部分。但是这个错误似乎已经重新出现了。查看Cumulative update package 4 for SQL Server 2008 R2 Service Pack 1 - 发布的帖子SP1。

970198      FIX: You receive an incorrect result when you run a 
            query that uses the row_number function in SQL Server 2008 
            or in SQL Server 2008 R2

在associated KB article MS中删除了对distinct的引用：

Consider the following scenario. You run a query against a table that has a 
clustered index in Microsoft SQL Server 2008 or in Microsoft SQL Server 2008
R2. In the query, you use the row_number function. In this scenario, you 
receive an incorrect result when a parallel execution plan is used for the 
query. If you run the query many times, you may receive different results.

这似乎证实了我之前对KB 2433265的解读 - 这句话暗示不同只是可能导致行为的许多条件之一。似乎并行执行计划是这次的罪魁祸首。

SQL Server LEFT JOIN无法匹配没有JOIN提示的行

1 个答案: