SELECT COUNT(*) all,  COUNT(NVL(state, 0, 1)) state0, COUNT(NVL(state, 1, 1)) state1, COUNT(NVL(state, 2, 1)) state2....
  FROM t

select state, count(*) from t group by rollup (state)

select count(*), count(where state = 0), count(where state = 1)... into l_total, l_zero, l_one,.. from t

А>select count(*), count(where state = 0), count(where state = 1)... into l_total, l_zero, l_one,.. from t
А>

select 
(
    select count(*)
    from t
),
(
    select count(*)
    from t
    where state = 0
),
(
    select count(*)
    from t
    where state = 1
),
(
    select count(*)
    from t
    where state = 2
),
(
    select count(*)
    from t
    where state = 3
) into total, one, two, three, four
from dual;

А>select count(*), count(where state = 0), count(where state = 1)... into l_total, l_zero, l_one,.. from t
А>

select count(*), sum(decode(state,0,1,0)), sum(decode(state,1,1,0)), sum(decode(state,2,1,0))... into l_total, l_zero, l_one, l_two,.. from t