Delete duplicate rows from table

Question

I have unique keys id keys in my table but I have a column with duplicate values? how do I get rid of those, while preserving only one of them like this :

Duplicate

Answer 1

Using Rank, actually I'm not totally sure about the syntax because I'm not that good at PostgreSQL, this is just a hint anyway (anybody's correction will be appreciated):

DELETE FROM mytable
WHERE id NOT IN
(
   SELECT x.id FROM
   (
      SELECT id, RANK() OVER (PARTITION BY name ORDER BY id ASC) AS r
      FROM mytable
   ) x
   WHERE x.r = 1
)