create extension if not exists pgcrypto;
drop table if exists funds;

-- creating a table with duplicate values for k.
create table funds(k integer, u uuid default gen_random_uuid(), v integer);

insert into funds(k, v) values (1, 1);
insert into funds(k, v) values (1, 1);
insert into funds(k, v) values (1, 1);

-- deduplicate rows with same k. Keep only the one with largest value of u.
delete from funds f1
      using funds f2
   where f1.u < f2.u and f1.k = f2.k;

select * from funds;

delete from funds f1
      using funds f2
   where f1.u < f2.u and f1.k = f2.k;
DELETE 3

select * from funds;
 k |                  u                   | v
---+--------------------------------------+---
 1 | bb7e5ed3-2cf8-45be-8c3e-e568c7e8b4ba | 1