How to delete duplicate rows
Today I want to give you an example of how delete duplicate rows from a table

Let’s create new table with name students:

CREATE TABLE students (ID NUMBER, NAME VARCHAR2(10), surname VARCHAR2(10))

Now let’s add some duplicate rows to it:

INSERT INTO students VALUES (1, ‘Nitesh’, ‘Jauhari’);
INSERT INTO students VALUES (2, ‘Edward’, ‘Smith’);
INSERT INTO students VALUES (1, ‘Nitesh’, ‘Jauhari’);
INSERT INTO students VALUES (2, ‘Edward’, ‘Smith’);
INSERT INTO students VALUES (1, ‘Nitesh’, ‘Jauhari’);
INSERT INTO students VALUES (2, ‘Edward’, ‘Smith’);
And now let’s look to the data of our table:
SELECT * FROM students
1  Nitesh  Jauhari
2  Edward   Smith
1  Nitesh  Jauhari
2  Edward   Smith
1  Nitesh  Jauhari
2  Edward   Smith
Now let’s delete duplicate rows using this script:

DELETE FROM students  
WHERE ROWID NOT IN (SELECT MAX (ROWID) FROM students GROUP BY ID)

And now let’s look to students table

SELECT * FROM students

1  Nitesh  Jauhari
2  Edward   Smith


Thanks.
NJ