Task 15: Delete Duplicate records

      Methods to remove duplicate records in SQL Server:

1. When we receive more than one rows of records, we need to remove the row which is not the first one and we can do this like below:


/* Delete Duplicate records */
WITH CTE (col1,col2,col3, DuplicateCount) 
AS 
(
SELECT col1,col2,col3, ROW_NUMBER() OVER (PARTITION BY col1,col2,col3 ORDER BY col1) AS DuplicateCount
FROM table_name 
)
DELETE FROM CTE 
WHERE DuplicateCount > 1