脏读:事务A读到了事务B已更新但未提交的数据；
| 事务A | 事务B | |
|---|---|---|
| SET autocommit = 0; | SET autocommit = 0; | |
| select money From test where id=1;Res: 100 | select money From test where id=1;Res: 100 | |
| update test set money=666 where id=1;Res: Query OK, 1 row affected (0.00 sec) | ||
| select money From test where id=1; | ||
| Res: 666 | commit; Query OK, 0 rows affected (0.00 sec) |