1、删除列
03:44:40 SQL> create table test as select * from emp;
Table created.
03:45:06 SQL> desc test;
Name Null Type
---------------------------------------------------------------------- -------- -----------------
EMPNO NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER(7,2)
COMM NUMBER(7,2)
DEPTNO NUMBER(2)
03:45:10 SQL> alter table test drop column comm;
Table altered.
03:45:26 SQL> desc test;
Name Null Type
---------------------------------------------------------------------- -------- -----------------
EMPNO NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER(7,2)