How to delete duplicate entries from table without deleting single entry in SQL

How to delete duplicate entries  from table without deleting single  entry in SQL

Suppose there are 5 duplicate  entries with same values in [MyTable] table, we have to keep only one entry in the table. 

When we  use the given code then 4 entries will be deleted

set rowcount 4


delete from MyTable where Myid =4  

set rowcount 0