create table test (col1 integer, col2 timestamp not null default clock_timestamp(), col3 integer);
insert into test (col1, col3) values (1234, 1);
insert into test (col1, col3) values (7890, 2);
insert into test (col1, col3) values (7890, 3);
insert into test (col1, col3) values (1235, 4);
insert into test (col1, col3) values (1234, 6);
insert into test (col1, col3) values (1235, 7);

select a.* from test a join (select col1, min(col2) order_key_1 from test group by col1) b on a.col1=b.col1 order by order_key_1, col2