create table t1(a number, b varchar(10));
insert into t1 values(123 , 'value1');

select count(*) from dual;
select * from dual;
select count(*) from t1;

select 
sql_id sql_id_,
sql_child_number sql_child_num,
module module_,
action action_,
logon_time lgtime,
v$session.*
from v$session
where 
type='USER'
and username='MY_USER'
and osuser = 'OS_USER'
and module = 'SQL*Plus'
order by lgtime desc

select * from t1

SQL> create table t1(a number, b varchar(10));

Table created.
SQL> insert into t1 values(123 , 'value1');

1 row created.

SQL> commit;

Commit complete.

SQL> select sys_context('userenv','sid') from dual;
SYS_CONTEXT('USERENV','SID')
--------------------------------------------------------
158

1 row selected.

SQL> select * from t1;
         A B
---------- ----------
       123 value1

1 row selected.

SQL> select sql_id, prev_sql_id from v$session where sid=158;
SQL_ID        PREV_SQL_ID
------------- -------------
              27uhu2q2xuu7r

1 row selected.

SQL> select SQL_TEXT from v$sql where sql_id='27uhu2q2xuu7r';
SQL_TEXT
------------------------------------------------------------------
select * from t1

1 row selected.

08:17:47 SQL> set autotrace traceonly explain
08:18:02 SQL> select sysdate from dual;

Execution Plan
----------------------------------------------------------
Plan hash value: 1388734953

-----------------------------------------------------------------
| Id  | Operation	 | Name | Rows	| Cost (%CPU)| Time	|
-----------------------------------------------------------------
|   0 | SELECT STATEMENT |	|     1 |     2   (0)| 00:00:01 |
|   1 |  FAST DUAL	 |	|     1 |     2   (0)| 00:00:01 |
-----------------------------------------------------------------

08:18:11 SQL>