Oracle PL/SQL Tutorial/Table/Drop Column
Drop a just added column
<source lang="sql">
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></source>