Mysql 存储过程、临时变量定义、IF、Case

-- Mysql 存储过程
/*
set @result = 0;
create procedure login(		-- 定义参数，有in、out、inout三种类型
in user varchar(10),
in pass varchar(10),
out result int
)
begin
declare passd varchar(10);-- declare 声明临时变量、类型，然后用set 进行赋值，declare 临时变量只能放在begin end 区域中，而其作用域也只是在begin end 中, 而 set @ 定义的变量是全局变量
select password into passd from login where username=user;
if passd like pass then	--  If 语句，后面要加上 End IF,就像是case 后也要加 End Case  一样
select 'Login Success' as Massage;
set result = 1;
else
select 'Login Failed' as Message;
set result =0;
end if;
end;
*/

-- 调用存储过程  call login('root','root',@result);
-- 删除存储过程  drop procedure login

create procedure translate(
id int
)
begin
case id
when 1 then
select 'one' as trans;
when 2 then
select 'two' as trans;
when 3 then
select 'three' as trans;
else
select 'no trans' as trans;
end case;
end;

/*

case 用法有两种：
1. 条件变量在when 中
select name, case
when age>10 then xxxxx
else
xxxxxx
end case
2. 条件变量在case 中
select name,case age
when >10 then xxx
else xxxxxs
end case
*/