How do I get the number (session ID) of the Oracle current sessions? __oracle

The following should be used by everyone.

Sql> SELECT SID from v$mystat WHERE rownum = 1;

Sid
———-
19949

The following is simpler, but can only be used in Oracle 10g and above.

sql> SELECT USERENV (' SID ') from DUAL;

USERENV (' SID ')
————–
19949

I sometimes use the following method because I don't want to write a subquery with the top SQL, I find it normal on Oracle 9i, but I often return two lines on Oracle 10g, so I can't use it any more.

Sql> SELECT SID from v$session WHERE audsid=userenv (' SESSIONID ');

Sid
———-
19949
19829