When you use a SELECT DISTINCT operation from another table to insert data into an empty table, you expect for a unique index to be built on the table. However, the attempt to create a unique index may fail with the following 1505 error message for data that was implicitly converted during the insert:
Server: Msg 1505, Level 16, State 1, Line 1 CREATE UNIQUE INDEX terminated because a duplicate key was found for index ID %d. Most significant primary key is '%S_KEY'.
This behavior can occur if, for certain implicit data type conversions, the DISTINCT operation is performed at the wrong time and fails to remove all of the duplicate rows.
To resolve this problem, obtain the latest service pack for Microsoft SQL Server 2000. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
290211 INF: How to Obtain the Latest SQL Server 2000 Service Pack
To work around this issue, create the unique index with the IGNORE_DUP_KEY clause before you insert the data.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.
This problem was first corrected in Microsoft SQL Server 2000 Service Pack 2.
Some examples of implicit conversions include the following:
char to nchar (Unicode)
smalldatetime to datetime
For more information about implicit conversions, see the following topics in Books Online:
Data Type Conversion
CAST and CONVERT
datatype data type wrong incorrect collate unicode