Dealing with MS SQL Tables that contain Duplicate Rows
Every so often, you might have to deal with tables that contain duplicate rows. In one case, you might only need to identify the duplicate rows. In other cases, you might need to remove the duplicate rows. This article will show you some different techniques for dealing with duplicate rows.
Your interpretation of a duplicate row might mean something different then the meaning to someone else. A duplicate row could mean that the data that makes up the key for each row is duplicated on more than one row. Another definition might be every column in a row matches with another row in the same table. I will show you how to find the duplicate rows in both of these cases.
Identifying Duplicate Key Values
One of the first things you will need consider when dealing with duplicates is how to identify the rows that contain duplicate values. To identify duplicates, you need to determine what is considered a duplicate record.