摘要：
--使用列位置排序select deptno,dname from dept union select empno ,ename from emp order by 1 desc; 阅读全文
摘要：
create or replace procedure add_em (eno number,name varchar2,sal number, job varchar2 default 'CLERK',dno number) is e_integrity exception; pragma exception_init(e_integrity,-2291); begin insert into... 阅读全文