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SQL

How to delete duplicate rows in sql?

| | SQL

Here I am using CTE(Common Table Expression) for Delete duplicate rows.


PARTITION BY : It devides the query result into partitions


Row_NUMBER : gives unique name for all duplicate rows ie., if one row record repeated for 3 times . it gives the index such as 1,2 and 3


Using this query we can delete all duplicate rows in a table


With EmployeeCTE AS
(
Select *, ROW_NUMBER() Over (Partition BY ID order by ID)as RowIndex
from tbl_Employees

)

--- Here we are going to delete all duplicate records except one record(original)


Delete from EmployeeCTE Where RowIndex > 1