SQL>
SQL> SELECT username, default_tablespace
2 FROM dba_users
3 where rownum<50
4 GROUP BY default_tablespace, username;
USERNAME DEFAULT_TABLESPACE
------------------------------ ------------------------------
SYS SYSTEM
SYSTEM SYSTEM
CTXSYS SYSAUX
RNTSOFT 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>