UC知道use pubs
来源：百度知道 编辑：UC知道 时间：2024/05/31 16:34:05
use pubs
if exists select name from sysobjects
where name=’author_infor’ and type=’p’
drop procedure author_infor
go
create procedure author_infor as
select au_lname, au_fname, title, pub_name
from authors a inner join titleauthor ta
on a.au_id=ta.au_id inner join titles t
on t.title_id=ta.title_id inner join publishers p
on t.pub_id=p.pub_id
go
那位大哥可以帮我每一句作个解释啊?分不多,请见谅
if exists select name from sysobjects
where name=’author_infor’ and type=’p’
drop procedure author_infor
go
create procedure author_infor as
select au_lname, au_fname, title, pub_name
from authors a inner join titleauthor ta
on a.au_id=ta.au_id inner join titles t
on t.title_id=ta.title_id inner join publishers p
on t.pub_id=p.pub_id
go
那位大哥可以帮我每一句作个解释啊?分不多,请见谅
use pubs /*是说在pubs数据库中查询语句*/
if exists select name from sysobjects
where name=’author_infor’ and type=’p’
drop procedure author_infor
go /*这是说，如果在sysobjects表中存在name=’author_infor’和 type=’p’ 做drop procedure author_infor ，然后在执行下面的语句*/
select au_lname, au_fname, title, pub_name
from authors a inner join titleauthor ta
on a.au_id=ta.au_id inner join titles t
on t.title_id=ta.title_id inner join publishers p
on t.pub_id=p.pub_id
go
这里的语句是说将authors 用 a 来代替，将titleauthor用 ta 来代替，然后在满足条件 t.title_id=ta.title_id inner join publishers p on t.pub_id=p.pub_id
再进行连接，这是一个表的连接问题.