mysql生成随机时间

mysql> update test set create_time=concat(‘2013-10-01 ‘, floor(10+rand()*10),‘:‘,floor(10+rand()*49),‘:‘,floor(10+rand()*49))  where create_time=‘0000-00-00 00:00:00‘;
Query OK, 1 row affected
Rows matched: 1  Changed: 1  Warnings: 0