UNIX_TIMESTAMP(), UNIX_TIMESTAMP(date)

如果不帶參數調用，返回一個Unix時間戳(自“1970-01-0100:00:00”UTC)作為無符號整數。如果UNIX_TIMESTAMP()被調用有一個日期參數，它返回的參數為秒，自“1970-01-0100:00:00”UTC的數值。日期可能是一個DATE字符串，一個DATETIME字符串，一個TIMESTAMP或數字格式YYYYMMDD或YYYYMMDD。

mysql> SELECT UNIX_TIMESTAMP();
+---------------------------------------------------------+
| UNIX_TIMESTAMP()                                        |
+---------------------------------------------------------+
| 882226357                                               |
+---------------------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT UNIX_TIMESTAMP('1997-10-04 22:23:00');
+---------------------------------------------------------+
| UNIX_TIMESTAMP('1997-10-04 22:23:00')                   |
+---------------------------------------------------------+
| 875996580                                               |
+---------------------------------------------------------+
1 row in set (0.00 sec)