Oracle Session in Shared Pool

select sid,
username,
round(total_user_mem/1024/1024,2) mem_used_in_mb,
round(100 * total_user_mem/total_mem,2) mem_percent
from
(select
b.sid sid,
nvl(b.username,p.name) username,
sum(value) total_user_mem
from
sys.v_$statname c,
sys.v_$sesstat a,
sys.v_$session b,
sys.v_$bgprocess p
where
a.statistic#=c.STATISTIC# and
p.paddr (+) = b.paddr and
b.sid=a.sid and
c.name in ('session pga memory','session uga memory')
group by
b.sid, nvl(b.username,p.name)),
(select
sum(value) total_mem
from
sys.v_$statname c,
sys.v_$sesstat a
where
a.statistic#=c.STATISTIC# and
c.name in ('session pga memory','session uga memory'))
order by 3 desc;