Retrieve session specific settings for previous "alter session" command

-- SQL> col name for a30
-- SQL> col sys_level for a20
-- SQL> col ses_level for a20
-- SQL> select p1.name,
--   2  p1.value sys_level,
--   3  p2.value ses_level
--   4  from v$system_parameter p1,
--   5  v$parameter p2
--   6  where p1.name=p2.name
--   7  and p1.value <> p2.value
--   8  order by p1.name
--   9  /
-- 
-- NAME                           SYS_LEVEL            SES_LEVEL
-- ------------------------------ -------------------- --------------------
-- sql_trace                      FALSE                TRUE


col name for a30
col sys_level for a20
col ses_level for a20
select p1.name,
p1.value sys_level,
p2.value ses_level
from v$system_parameter p1,
v$parameter p2
where p1.name=p2.name
and p1.value <> p2.value
order by p1.name
/