Which user executing what type of command | Oracle DBA Tutorial pdf

Which user executing what type of command

SELECT
SID,
SERIAL#,
v.schemaname,
DECODE(COMMAND
,0,'None'
,2,'Insert'
,3,'Select'
,6,'Update'
,7,'Delete'
,8,'Drop'
,26,'Lock Table'
,44,'Commit'
,45,'Rollback'
,47,'PL/SQL Execute'
,'Other') command
FROM V$SESSION v