How to delete duplicate records from table without copying data to another table ...

Answer 1

Delete from table_name where (rowid, columns name) not in (select min(rowid), column_name from table_name group by column_name) ;

Answer 2

If you are using SQL Server, you could use DELETE TOP 1.

Ex:

Suppose you have a table as below:

id name
---------------
1 Tiger
2 Cat
1 Tiger
4 Monkey
2 Cat
-----------------

DELETE TOP 1 FROM table1
WHERE
id IN (SELECT id FROM table1
GROUP BY id
HAVING COUNT (*)>1);