mysql中timestamp自動更新

CREATE TABLE `ts` (                                                               
          `ts1` timestamp NOT NULL ,
          `ts2` timestamp NOT NULL default CURRENT_TIMESTAMP,
    `ts3` timestamp NULL default NULL                           
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8

錯誤碼: 1293
Incorrect table definition; there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE clause

Execution Time : 00:00:00:000
Transfer Time : 00:00:00:000
Total Time     : 00:00:00:000

建立的時候ts1 跟ts2 是一樣的，只能有一個更新的時候更新

CREATE TABLE `ts` (                                                               
        
      `ts2` timestamp NOT NULL default CURRENT_TIMESTAMP,
    `ts3` timestamp NULL default NULL                           
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8
這樣子更新後的ts2不會自動更新

CREATE TABLE `ts` (                                                               
      `ts1` timestamp NOT NULL ,      
    `ts3` timestamp NULL default NULL                           
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8
插入之後SQL語句變成了
CREATE TABLE `ts` (                                                               
          `ts1` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP,
          `ts3` timestamp NULL default NULL                                               
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8      

   `ts1` timestamp NOT NULL , => `ts1` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP,
                                       
這時更新的時候就會自動更新ts1欄位了，不想要更新就建立的時候加各default
`ts2` timestamp NOT NULL default CURRENT_TIMESTAMP,

預設為空白是 `ts3` timestamp NULL default NULL        而不是 `ts3` timestamp default NULL