(0) 如题

(1) 比如转账/扣款相关的业务，推荐用悲观锁还是乐观锁?

(2) 脑补了如下的乐观锁实现，可以满足并发转账和取钱需求吗?

(3) 如果能，那么和悲观锁 select for update 作对比哪个更好?

# 数据库初始状态
TRUNCATE account;
INSERT INTO account (id, name, balance, version)
VALUES (1, 'ichigo', 10, 1),
       (2, 'rukia', 10, 1);

# 并发事务 1 转出全部余额
START TRANSACTION;
SELECT balance, version FROM account WHERE id = 1;
SELECT version FROM account WHERE id = 2;
UPDATE account SET balance = balance - 10, version = 2 WHERE id = 1 AND version = 1;
UPDATE account SET balance = balance + 10, version = 2 WHERE id = 2 AND version = 1;
COMMIT;

# 并发事务 2 取出全部余额
START TRANSACTION;
SELECT balance, version FROM account WHERE id = 1;
UPDATE account SET balance = balance - 10, version = 2 WHERE id = 1 AND version = 1;
COMMIT;