存储过程
1 创建存储过程
create proc stu_proc1
as select count(*) from student
exec stu_proc1 执行
2 修改、删除、重命名
alter proc stu_proc1
as select * from student
drop proc stu_proc1
sp_rename stu_proc1 old
3 参数存储过程
传入参数:
create proc stu_proc3
@pname char(3)
as select * from student where number=@pname
exec stu_proc3 '103'
传出参数:
create proc stu_proc5
@pname char(3),
@result char(8) output
as select @result=name from student where number=@pname
declare @a char(8)
exec stu_proc5 '103',@a output
print @a//select @a
亦可命名参数、明确指定
declare @a char(8)
exec stu_proc5 @result=@a output,@pname='103'
print @a
4 存储过程的复杂操作
使用带有复杂 SELECT 语句的简单过程
下面的存储过程从两个表的联接中返回所有学生(提供了姓名)、所学课程。
该存储过程不使用任何参数。
USE students
IF EXISTS (SELECT name FROM sysobjects WHERE name = 'info_all' AND type = 'P')
DROP PROCEDURE info_all
GO
CREATE PROCEDURE info_all
AS
SELECT stu.name,grade.course
FROM stu INNER JOIN grade ON stu.number = grade.number
GO
info_all 存储过程可以通过以下方法执行:
EXECUTE info_all
-- Or
EXEC info_all
下面的存储过程从四个表的联接中返回所有作者(提供了姓名)、出版的书籍以及出版社。该存储过程不使用任何参数。
USE pubs
IF EXISTS (SELECT name FROM sysobjects
WHERE name = 'au_info_all' AND type = 'P')
DROP PROCEDURE au_info_all
GO
CREATE PROCEDURE au_info_all
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
练习1:制作存储过程显示所有年龄大于26的学生
create proc age1
as
select name from student
where year(getdate())-year(birthday)>26
exec age1
练习2:制作存储过程显示所有年龄大于指定大小的学生
create proc age2
@pdata int
as
select name from student
where year(getdate())-year(birthday)>@pdata
exec age2 26
存储过程的注意事项:可使用with recompile 和with encryption
两者都可放在参数之后,语句之前
其中with recompile会导致每次调用存储过程都会编译,效率变低,但执行效率可能优化,
或加入到exec age with recompile中,则会根据需要创造新的查询计划
多行储存过程
create proc temp
as
select * from stu
select * from grade