How to obtain the ID (Session ID) of the current Oracle Session)

There are three methods to obtain the current Session ID (Session ID) of Oracle:

1.Below, this should be common.

SQL>Select sid from v $ mystat where rownum = 1;

SID

----------

140

2.The following is simpler:,HoweverOracle 10gAnd later versions.

SQL>Select userenv ('sid ') from dual;

USERENV ('sid ')

--------------

140

3.I use the following method sometimes.,Because you don't want to use the topSQLWrite a subquery,Found inOracle 9iNormal,HoweverOracle 10gUsually two rows are returned.,So you can no longer use it..

SQL>Select sid from v $ session where audsid = USERENV ('sessionid ');

SID

----------

140

142