SQL之存储过程

--定义变量
declare @a int
--变量赋值
set @a =1
print @a

--变量结合查询语句
--不跟菠萝一个产地的水果信息
select *from fruit where source not in (
select source from fruit where name ='菠萝'
)

declare @source varchar(50)
select @source =source from fruit where name ='菠萝'
select *from fruit where source != @source

--在查询语句中也可以对一个变量赋值放在select和from中间
--set 单纯用来给变量赋值不具备查询映射的功能
--当from后面显示多个值又给他赋值之后他会把最后一条去掉

update fruit set numbers =98 where ids='k001'
update fruit set numbers =88 where ids='k002'
update fruit set numbers =78 where ids='k003'
update fruit set numbers =99 where ids='k004'
update fruit set numbers =55 where ids='k005'

--查询菠萝的数量和橘子的数量比较菠萝和橘子的数量多少

declare @boluo int,@juzi int
select @boluo =numbers from fruit where ids ='k002'
select @juzi =numbers from fruit where ids ='k003'
if @boluo>@juzi
begin
print'菠萝数量多'
end
else
begin
print '橘子数量多'
end

--累加求和

declare @a int
set @a =10
declare @sum int,@i int
set @sum =0
set @i =1

while @i<=@a
begin
set @sum =@sum+@i
set @i =@i+1
end
print @sum

--存储过程相当于c#里面的函数
--as 和存储过程名之间写输入参数输出参数,不需要指明返回值

create proc leijia
@a int

as
declare @sum int,@i int
set @sum =0
set @i =1

while @i<=@a
begin
set @sum =@sum+@i
set @i =@i+1
end
return @sum

go
--exec 调用需要定义一个返回值接收
declare @sum int --定义一个返回值接收

exec @sum =leijia 10--调用返回值写在exec后面存储过程名跟参数多个参数用逗号隔开
print @sum

存储过程输出参数

alter proc leijia 修改存储过程
@a int,
@b int out
as
declare @sum int,@i int
set @sum =0
set @i =1

while @i<=@a
begin
set @sum =@sum+@i
set @i =@i+1
end
set @b=5
return @sum

go
--exec 调用需要定义一个返回值接收
declare @sum int ,@b int--定义一个返回值接收

exec @sum =leijia 100,@b out--调用返回值写在exec后面存储过程名跟参数多个参数用逗号隔开
print @sum
print @b

SQL之存储过程

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