FIX: Select Distinct Fails to Eliminate Duplicate Null Values on Bit Datatype

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Article ID: 281338 - View products that this article applies to.
This article was previously published under Q281338
This article has been archived. It is offered "as is" and will no longer be updated.
BUG #: 26147 (SQLBUG_70)
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SYMPTOMS

Select distinct does not eliminate duplicate null values that are contained in bit datatype columns.

STATUS

Microsoft has confirmed this to be a problem in SQL Server 7.0. This problem has been corrected in U.S. Service Pack 3 for Microsoft SQL Server 7.0. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
274799 INF: How to Obtain Service Pack 3 for Microsoft SQL Server 7.0 and Microsoft Data Engine (MSDE) 1.0
For more information, contact your primary support provider.

MORE INFORMATION

Use the code that follows to reproduce this behavior:
create table #myTable( bar bit)
go
insert into #mytable values (1)
insert into #mytable values (1)
insert into #mytable values (NULL)
insert into #mytable values (NULL)
go
select distinct bar from #mytable
go
				
The preceding code returns this result:
bar  
---- 
NULL
NULL
1
				
Note that the code correctly eliminates the duplicate value 1 but incorrectly returns duplicate null values. The correct resultset is:
bar  
---- 
NULL
1
				

Properties

Article ID: 281338 - Last Review: October 21, 2013 - Revision: 2.1
APPLIES TO
  • Microsoft SQL Server 7.0 Standard Edition
Keywords: 
kbnosurvey kbarchive kbbug kbfix KB281338

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