Oracle PL/SQL Tutorial/System Tables Data Dictionary/all tables

Get information on all the tables you have access to using all_tables

SQL>
SQL> desc all_tables;
 Name                             Null?    Type
 OWNER                            NOT NULL VARCHAR2(30)
 TABLE_NAME                       NOT NULL VARCHAR2(30)
 TABLESPACE_NAME                           VARCHAR2(30)
 CLUSTER_NAME                              VARCHAR2(30)
 IOT_NAME                                  VARCHAR2(30)
 STATUS                                    VARCHAR2(8)
 PCT_FREE                                  NUMBER
 PCT_USED                                  NUMBER
 INI_TRANS                                 NUMBER
 MAX_TRANS                                 NUMBER
 INITIAL_EXTENT                            NUMBER
 NEXT_EXTENT                               NUMBER
 MIN_EXTENTS                               NUMBER
 MAX_EXTENTS                               NUMBER
 PCT_INCREASE                              NUMBER
 FREELISTS                                 NUMBER
 FREELIST_GROUPS                           NUMBER
 LOGGING                                   VARCHAR2(3)
 BACKED_UP                                 VARCHAR2(1)
 NUM_ROWS                                  NUMBER
 BLOCKS                                    NUMBER
 EMPTY_BLOCKS                              NUMBER
 AVG_SPACE                                 NUMBER
 CHAIN_CNT                                 NUMBER
 AVG_ROW_LEN                               NUMBER
 AVG_SPACE_FREELIST_BLOCKS                 NUMBER
 NUM_FREELIST_BLOCKS                       NUMBER
 DEGREE                                    VARCHAR2(10)
 INSTANCES                                 VARCHAR2(10)
 CACHE                                     VARCHAR2(5)
 TABLE_LOCK                                VARCHAR2(8)
 SAMPLE_SIZE                               NUMBER
 LAST_ANALYZED                             DATE
 PARTITIONED                               VARCHAR2(3)
 IOT_TYPE                                  VARCHAR2(12)
 TEMPORARY                                 VARCHAR2(1)
 SECONDARY                                 VARCHAR2(1)
 NESTED                                    VARCHAR2(3)
 BUFFER_POOL                               VARCHAR2(7)
 ROW_MOVEMENT                              VARCHAR2(8)
 GLOBAL_STATS                              VARCHAR2(3)
 USER_STATS                                VARCHAR2(3)
 DURATION                                  VARCHAR2(15)
 SKIP_CORRUPT                              VARCHAR2(8)
 MONITORING                                VARCHAR2(3)
 CLUSTER_OWNER                             VARCHAR2(30)
 DEPENDENCIES                              VARCHAR2(8)
 COMPRESSION                               VARCHAR2(8)
 DROPPED                                   VARCHAR2(3)
SQL>
SQL> --select * from all_tables;

Query the all_tables

SQL>
SQL> desc all_tables;
 Name                                     Null?    Type
 -----------------------------------------
 OWNER                                    NOT NULL VARCHAR2(30)
 TABLE_NAME                               NOT NULL VARCHAR2(30)
 TABLESPACE_NAME                                   VARCHAR2(30)
 CLUSTER_NAME                                      VARCHAR2(30)
 IOT_NAME                                          VARCHAR2(30)
 STATUS                                            VARCHAR2(8)
 PCT_FREE                                          NUMBER
 PCT_USED                                          NUMBER
 INI_TRANS                                         NUMBER
 MAX_TRANS                                         NUMBER
 INITIAL_EXTENT                                    NUMBER
 NEXT_EXTENT                                       NUMBER
 MIN_EXTENTS                                       NUMBER
 MAX_EXTENTS                                       NUMBER
 PCT_INCREASE                                      NUMBER
 FREELISTS                                         NUMBER
 FREELIST_GROUPS                                   NUMBER
 LOGGING                                           VARCHAR2(3)
 BACKED_UP                                         VARCHAR2(1)
 NUM_ROWS                                          NUMBER
 BLOCKS                                            NUMBER
 EMPTY_BLOCKS                                      NUMBER
 AVG_SPACE                                         NUMBER
 CHAIN_CNT                                         NUMBER
 AVG_ROW_LEN                                       NUMBER
 AVG_SPACE_FREELIST_BLOCKS                         NUMBER
 NUM_FREELIST_BLOCKS                               NUMBER
 DEGREE                                            VARCHAR2(10)
 INSTANCES                                         VARCHAR2(10)
 CACHE                                             VARCHAR2(5)
 TABLE_LOCK                                        VARCHAR2(8)
 SAMPLE_SIZE                                       NUMBER
 LAST_ANALYZED                                     DATE
 PARTITIONED                                       VARCHAR2(3)
 IOT_TYPE                                          VARCHAR2(12)
 TEMPORARY                                         VARCHAR2(1)
 SECONDARY                                         VARCHAR2(1)
 NESTED                                            VARCHAR2(3)
 BUFFER_POOL                                       VARCHAR2(7)
 ROW_MOVEMENT                                      VARCHAR2(8)
 GLOBAL_STATS                                      VARCHAR2(3)
 USER_STATS                                        VARCHAR2(3)
 DURATION                                          VARCHAR2(15)
 SKIP_CORRUPT                                      VARCHAR2(8)
 MONITORING                                        VARCHAR2(3)
 CLUSTER_OWNER                                     VARCHAR2(30)
 DEPENDENCIES                                      VARCHAR2(8)
 COMPRESSION                                       VARCHAR2(8)
 DROPPED                                           VARCHAR2(3)
SQL>
SQL> select owner, table_name
  2  from all_tables
  3  where rownum < 30
  4  order by owner, table_name ;

OWNER                          TABLE_NAME
------------------------------ ------------------------------
SYS                            ATTRCOL$
SYS                            BOOTSTRAP$
SYS                            CCOL$
SYS                            CDEF$
SYS                            CLU$
SYS                            COL$
SYS                            COLTYPE$
SYS                            CON$
SYS                            FET$
SYS                            FILE$
SYS                            ICOLDEP$
SYS                            LIBRARY$
SYS                            LOB$
SYS                            NTAB$
SYS                            OBJ$
SYS                            OPQTYPE$
SYS                            PROXY_DATA$
SYS                            PROXY_ROLE_DATA$
SYS                            REFCON$
SYS                            SEG$
SYS                            SUBCOLTYPE$
SYS                            TAB$
SYS                            TS$
SYS                            TSQ$
SYS                            TYPE_MISC$
SYS                            UET$
SYS                            UNDO$
SYS                            USER$
SYS                            VIEWTRCOL$
29 rows selected.