实验1——Oracle数据查询

一、实验题目
Oracle数据查询设计
二、实验目的
熟悉统计查询、子查询、外连接查询、递归查询等高级查询设计。
三、实验内容
1、编写SQL创建视图view_getTeacherbyDeptID，获取信息技术学院及其下属部门的所有教师信息。

create or replace view view_getTeacherbyDeptID
as
select * from teacher 
where dept_id in (
  select dept_id from dept 
  start with dept_name='信息技术学院'
  connect by prior dept_id=parent_id
);

2、编写SQL创建视图view_getTeacherCountbyProfess，统计各个职称级别的教师人数。

create or replace view view_getTeacherCountbyProfess
as
select count(*) "教师人数",
decode(profess,'教授','1-教授','副教授','2-副教授','讲师','3-讲师','助教','4-助教')  "职称级别" 
from teacher 
group by profess
order by "职称级别";

3、编写SQL创建视图view_getCourseCountForTearch，统计任课表中各教师的授课数。

create or replace view view_getCourseCountForTearch
as
select 
count(*) "课程数",
teacher_id  "教师编号" ,
(select tname from teacher where teacher_id=tc.teacher_id) "教师姓名"
from tc 
group by teacher_id;

4、编写SQL创建视图view_getCourseCountForAllTearch，统计所有教师的授课数。

create or replace view view_getCourseCountForAllTearch
as
select a.*,b.c "授课数" from teacher a,
(select count(*) c,teacher_id from tc group by teacher_id) b
where a.teacher_id= b.teacher_id(+);