postgresql - find duplicates

postgresql_find_duplicates.sql

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

original here: https://stackoverflow.com/questions/14471179/find-duplicate-rows-with-postgresql/14471928#14471928

best alternative yet for me, in readability and performance, because it supports several fields and lists duplicate records except the "original" (dups.Row=1), so you can easily identify or delete the duplicates.

Another possibility I like:

select objectid, count(*)
from table where condition=value
group by objectid
HAVING count(*) > 1

Simple to read and remember...

original here: https://stackoverflow.com/questions/50805439/postgresql-fastest-way-to-get-duplicates