MySql事件无法正常工作

Question

我有这个mysql数据结构

 | create_t   | delete_t   |
 | 1479643496 | 1479643616 |
 | 1479643496 | 1479643616 |
 | 1479643637 | 1479643757 |

create_t和delete_t都是BigInt
我创建了这样的活动

CREATE EVENT assaassas
ON SCHEDULE EVERY 50 SECOND
    DO
DELETE FROM Test WHERE delete_time<='$date->getTimestamp()'"

但它毫无结果。