create table test(
id serial not null,
name text null,
price int, 
dept int 
)

INSERT into test values(1, 'A', 10, 1)
INSERT into test values(2, 'A', 20, 1)
INSERT into test values(3, 'A', 30, 2)
INSERT into test values(4, 'B', 10, 1)
INSERT into test values(5, 'B', 20, 2)

select name, sum(price) OVER( partition by dept)
from test
order by name

select name, sum(price) OVER( partition by dept order by name)
from arm
order by name