FIX: A query that uses the FOR XML AUTO clause generates different results in SQL Server 2000 and in SQL Server 2005

When you run a query that uses the FOR XML AUTO clause in Microsoft SQL Server 2005, the result differs from the result that you receive when you run the same query in SQL Server 2000. This problem occurs if the following conditions are true:

• The query uses a conversion function on a column.
• In the conversion function, the source column is same as the destination column. For example, the query uses the following conversion function on a column of the datetime data type:

  cast(ColumnA as datetime) as ColumnB

Additionally, if you set the database compatibility level of the instance to 80, and then you run the query again, the result is still different from the result in SQL Server 2000.

This issue occurs because the SQL Server 2005 database engine ignores the conversion function when the database engine compares the source column and the destination column when the source column and the destination column are same. However, the SQL Server 2000 database engine does not ignore the conversion function.

The fix for this issue was first released in Cumulative Update 5. For more information about how to obtain this cumulative update package for SQL Server 2005 Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base:Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2005 fix release. Microsoft recommends that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:Microsoft SQL Server 2005 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2005 Service Pack 2 hotfix to an installation of SQL Server 2005 Service Pack 2. By default, any hotfix that is provided in a SQL Server service pack is included in the next SQL Server service pack.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

After you apply this hotfix, you receive a consistent result between SQL Server 2000 and SQL Server 2005 when you set the database compatibility level of the instance to 80 in the scenario that the "Symptoms" section describes.

Steps to reproduce the problem

1. Install the Northwind sample database on an instance of SQL Server 2005 and on an instance of SQL Server 2000.
2. Run the following query in both of the two instances of SQL Server:

   select top 1 t1.orderid
    ,t1.customerid
    ,t2.productid
    ,t1.shipregion
    ,cast(t2.unitPrice as money) unitPrice
    ,cast(t1.OrderDate as datetime) as OrderDate
    from orders t1
    join [order Details] t2 on t1.orderid= t2.orderid
    where shipregion is not null
    for xml auto
   

In the instance of SQL Server 2000, you receive the following result:In the instance of SQL Server 2005, you receive the following result:For more information about what files are changed, and for information about any prerequisites to apply the cumulative update package that contains the hotfix that is described in this Microsoft Knowledge Base article, click the following article number to view the article in the Microsoft Knowledge Base:

For more information about the list of builds that are available after SQL Server Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the Incremental Servicing Model for SQL Server, click the following article number to view the article in the Microsoft Knowledge Base:For more information about how to obtain SQL Server 2005 Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the new features and the improvements in SQL Server 2005 Service Pack 2, visit the following Microsoft Web site: For more information about the naming schema for SQL Server updates, click the following article number to view the article in the Microsoft Knowledge Base:For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: