mysql 存储过程 基础例子

DELIMITER //  -- 定义分隔符，防止作为sql语句执行
drop procedure if exists pr_add;
create procedure pr_add( )
begin
declare c int;
set c = 2;
if c = 1 then
insert into ONLINE_USER_INFO values(1,'admin','厉害了','');
else delete from ONLINE_USER_INFO where user_code = 1;
end if;
while c < 10 do
insert into ONLINE_USER_INFO values(c+2,'admin','厉害了','');
set c = c + 1;
end while;
test_loop:loop
delete from ONLINE_USER_INFO where user_code = c-2;
set c = c - 1;
if c < 8 then
leave test_loop;
end if;
end loop;
end //   -- 必须，否则创建存储过程失败
DELIMITER ;
call pr_add();

2.事务回滚
DELIMITER // -- 定义分隔符，防止作为sql语句执行
drop procedure if exists pr_add;
create procedure pr_add( )
begin
declare c int;
declare t_error INTEGER default 0;
DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET t_error=1; --出现sql异常则设置t_error为1
set c = 1;
START TRANSACTION; --开启事务
if c = 1 then
insert into ONLINE_USER_INFO values(1,'admin','厉害了','');
else delete from ONLINE_USER_INFO where user_code = 1;
end if;
while c < 10 do
insert into ONLINE_USER_INFO values(c+2,'admin','厉害了','');
set c = c + 1;
end while;
test_loop:loop
delete from ONLINE_USER_INFO where user_code = c-2;
set c = c - 1;
if c < 8 then
insert into ONLINE_USER_INFO values('admin','厉害了',''); --出现异常
leave test_loop;
end if;
end loop;
if t_error = 1 then
ROLLBACK; --执行回滚操作
else
commit; --提交sql操作
end if;
end // -- 存储的结束
DELIMITER ;
call pr_add()