Oracle PL/SQL Tutorial/SQL PLUS Session Environment/Usename

Count user name

   <source lang="sql">

SQL> SQL> SELECT COUNT(username) users, default_tablespace

 2  FROM dba_users
 3  where rownum<50
 4  GROUP BY default_tablespace
 5  /
    USERS DEFAULT_TABLESPACE

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        6 SYSAUX
        2 USERS
        7 SYSTEM

SQL></source>

SELECTs using the GROUP BY clause.

   <source lang="sql">

SQL> SQL> SELECT username, default_tablespace

 2  FROM dba_users
 3  where rownum<50
 4  GROUP BY default_tablespace, username;

USERNAME DEFAULT_TABLESPACE

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SYS SYSTEM SYSTEM SYSTEM CTXSYS SYSAUX sqle SYSTEM OUTLN SYSTEM DIP SYSTEM HR USERS ANONYMOUS SYSAUX PLSQL USERS TSMSYS SYSTEM FLOWS_FILES SYSAUX XDB SYSAUX MDSYS SYSTEM DBSNMP SYSAUX FLOWS_020100 SYSAUX 15 rows selected. SQL></source>