Oracle PL/SQL Tutorial/Table/Drop Column

Drop a just added column

SQL>
SQL>
SQL> create table registrations
  2  ( attendee    NUMBER(4)
  3  , course      VARCHAR2(6)
  4  , begindate   DATE
  5  , evaluation  NUMBER(1)) ;
Table created.
SQL>
SQL>
SQL> insert into registrations values (1, "SQL",date "1999-04-12",4   );
1 row created.
SQL> insert into registrations values (2, "SQL",date "1999-12-13",NULL);
1 row created.
SQL> insert into registrations values (3, "SQL",date "1999-12-13",NULL);
1 row created.
SQL> insert into registrations values (4, "OAU",date "1999-08-10",4   );
1 row created.
SQL> insert into registrations values (5, "OAU",date "2000-09-27",5   );
1 row created.
SQL> insert into registrations values (6, "JAV",date "1999-12-13",2   );
1 row created.
SQL> insert into registrations values (7, "JAV",date "2000-02-01",4   );
1 row created.
SQL> insert into registrations values (8, "JAV",date "2000-02-01",5   );
1 row created.
SQL> insert into registrations values (9, "XML",date "2000-02-03",4   );
1 row created.
SQL> insert into registrations values (10,"XML",date "2000-02-03",5   );
1 row created.
SQL> insert into registrations values (1, "PLS",date "2000-09-11",NULL);
1 row created.
SQL> insert into registrations values (2, "PLS",date "2000-09-11",NULL);
1 row created.
SQL> insert into registrations values (3, "PLS",date "2000-09-11",NULL);
1 row created.
SQL>
SQL>
SQL> alter table registrations
  2  add  (entered_by number(4) default 7839 not null);
Table altered.
SQL>
SQL> alter table registrations
  2  drop  column entered_by;
Table altered.
SQL>
SQL> drop table registrations;
Table dropped.
SQL>