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Jan
19
comment SQL Server Indexing Performance in Unique/Duplicate column
I'm not sure I understand your question fully. If each value of a column is unique, one leaf node will point to one record, the best performance you can get. If there are more than one record with the same value then each of those records will have to be scanned individually. I always think of a phone book. A phone book is indexed on the first letter of each name, that only divides the records into 26 sections, you then have to scan each section for the name you want so it isn't a very ideal index.
Jan
19
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Jan
17
answered SQL Server Indexing Performance in Unique/Duplicate column