/*

一、

1、编写存储过程实现转账过程

2、提示：

(1)涉及t_user、t_account表，新建t_transfer_log表

(2)转账金额小于100，不收手续费，在100-1000范围收取0.1%的手续费，在1000-5000收取0.3%手续费，在5000-10000收取0.5%，大于10000收取1%手续费，封顶50块。

(3)记录转账日志

*/

# 新建t_transfer_log表

create table t_transfer_log(

transfer_id int(11) primary key auto_increment comment '转账编号',

sender_id int(11) not null comment '转出人编号',

receiver_id int(11) not null comment '收款人编号',

amount double(11,2) not null default 0.00 comment '转账金额',

fee double(11,2) not null default 0.00 comment '手续费',

status char(1) not null default '0' comment '转账状态：0-开始转账；1-转账中；2-转账成功；3-转账失败',

transfer_date datetime not null default current_timestamp comment '转账时间',

update_date datetime not null default current_timestamp on update current_timestamp comment '更新时间'

)engine=innodb default charset=utf8 comment '转账记录表';

# 编写存储过程实现转账过程

CREATE PROCEDURE proc_transfer (IN in_sender_id INT, IN in_receiver_id INT, in in_amount DOUBLE, OUT out_msg VARCHAR (20))

begin

# 转出人账余额

declare v_sender_balance double default 0.00;

# 手续费

declare v_fee double default 0.00;

# 转账记录id

declare v_transfer_id int;

# 语句执行标志

declare done int default 0;

# 语句执行错误修改执行标志

DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET done = 1;

# 获取转账记录的id

select max(transfer_id) into v_transfer_id from t_transfer_log where sender_id = in_sender_id;

# 查询转出人账户余额

select balance into v_sender_balance from t_account where user_id = in_sender_id;

# 计算转账金额

if in_amount <= 100 THEN

set v_fee = 0;

elseif in_amount > 100 and in_amount <= 1000 then

set v_fee = in_amount * 0.001;

elseif in_amount > 1000 and in_amount <= 5000 then

set v_fee = in_amount * 0.003;

elseif in_amount > 5000 and in_amount <= 10000 then

set v_fee = in_amount * 0.005;

else

set v_fee = in_amount * 0.01;

end if;

# 判断手续费是否到达50封顶

if v_fee > 50 then

set v_fee = 50;

end if;

# 创建转账日志

insert into t_transfer_log(sender_id, receiver_id, amount, fee) values (in_sender_id, in_receiver_id, in_amount, v_fee);

# 开启事务

start transaction;

# 判断账户余额是否大于或者等于转账金额+手续费

if v_sender_balance >= in_amount + v_fee THEN

# 修改转账记录的状态为转账中

update t_transfer_log set status = '1' where transfer_id = v_transfer_id;

# 转出人余额减区转账金额和手续费

update t_account set balance = balance - in_amount - v_fee where user_id = in_sender_id;

# 收款人余额减区转账金额

update t_account set balance = balance + in_amount where user_id = in_receiver_id;

# 修改转账记录的状态为转账失败

update t_transfer_log set status = '2' where transfer_id = v_transfer_id;

# 提示转账结果

set out_msg = '转账成功！';

else

# 提示转账结果

set out_msg = '余额不足，转账失败！';

# 修改转账记录的状态为转账失败

update t_transfer_log set status = '3' where transfer_id = v_transfer_id;

end if;

if done = 1 then

# 回滚事务

rollback;

# 修改转账记录的状态为转账失败

update t_transfer_log set status = '3' where transfer_id = v_transfer_id;

# 提示转账结果

set out_msg = '系统异常，转账失败！';

else

# 提交事务

commit;

end if;

end;

# 测试

set @msg = '';

call proc_transfer(1, 2, 10000, @msg);

select @msg;