How to find duplicate records in PostgreSQL

Question

I have a PostgreSQL database table called \"user_links\" which currently allows the following duplicate fields:

year, user_id, sid, cid

The uni

Answer 1

From "Find duplicate rows with PostgreSQL" here's smart solution:

select * from (
  SELECT id,
  ROW_NUMBER() OVER(PARTITION BY column1, column2 ORDER BY id asc) AS Row
  FROM tbl
) dups
where 
dups.Row > 1