Funkcja może być dla Ciebie wygodna:
create or replace function interval_in_hours(interval)
returns text language sql as $$
select format('%s:%s',
(extract (epoch from $1) / 3600)::int,
to_char($1, 'mi:ss'))
$$;
Użyj:
with the_data (id_task_tarefa, dt_inicio, dt_termino) as (
values
(211, timestamp '2016-01-25 10:40:25', timestamp '2016-01-27 08:51:02'),
(210, timestamp '2016-01-25 10:40:29', timestamp '2016-01-27 08:50:21')
)
select *, interval_in_hours(dt_termino- dt_inicio)::interval as sum
from the_data;
id_task_tarefa | dt_inicio | dt_termino | sum
----------------+---------------------+---------------------+----------
211 | 2016-01-25 10:40:25 | 2016-01-27 08:51:02 | 46:10:37
210 | 2016-01-25 10:40:29 | 2016-01-27 08:50:21 | 46:09:52
(2 rows)