Question

Using SQL Server 2008 and imported two files into a table. The first file (2048) has 6,721 rows, the second file has (2209) 4,707 rows and the columns are: Billed, FirstName, LastName, FileID. Table is called Claims.

Need query to list each FileId (2209 and 2048) showing the duplicates in each file and delete the duplicates from one of them.

Ran this query:

SELECT firstname
, lastname
, duplicatecount = COUNT(1)
FROM Claims
WHERE fileid IN (2209, 2048)
GROUP BY
firstname
, lastname
HAVING COUNT(1) > 1
ORDER BY COUNT(1) DESC

Answer 1

These are duplicates. So start with your query:

with todelete as (<your query here>)
delete from Claims
    from todelete
    where todelete.firstname = claims.firstname and
          todelete.lastname = claims.lastname and
          fileid = 2209

You want to delete the duplicate value, not all of them, so you need to specify which one to remove. I arbitrarily chose 2209.