MYSQL中TIMESTAMP类型的默认值(2)

t1      CREATE TABLE `t2` (                                     
          `p_c` int(11) NOT NULL,                                
          `p_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP
        ) ENGINE=InnoDB DEFAULT CHARSET=gb2312                 
数据：
insert into t2(p_c) select 4;
update t2 set p_c = 3 where p_c = 5;
1    2007-10-08 11:53:35
2    2007-10-08 12:00:37
5    2007-10-08 12:00:37
4    2007-10-08 12:05:19
3、一个表中不能有两个字段默认值是当前时间，否则就会出错。不过其他的可以。
表：
———————————
Table   Create Table                                                  
———————————————————————
t1      CREATE TABLE `t1` (                                            
          `p_c` int(11) NOT NULL,                                     
          `p_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,      
          `p_timew2` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00'
        ) ENGINE=InnoDB DEFAULT CHARSET=gb2312                       
数据：
1    2007-10-08 11:53:35    0000-00-00 00:00:00
2    2007-10-08 12:00:37    0000-00-00 00:00:00