Question

    CREATE TABLE `tmp` (
    `CallID` bigint(8) unsigned NOT NULL,
    `InfoID` bigint(8) unsigned NOT NULL,
   `CallStartTime` datetime NOT NULL,
    KEY `CallStartTime` (`CallStartTime`)
  ) ENGINE=InnoDB DEFAULT CHARSET=latin1

在这个表中我想再添加一列PartitionID int（4）unsigned NOT NULL，这里我想要插入PartitionID列的数据，这意味着PartitionID =（DAYOFYEAR（'2009-01-01 00:00:00'））= 1 我想自动插入数据... PartitionID =（DAYOFYEAR（CallStartTime））

我的表格这样的旧数据

        (144,   56, '2011-06-19 1:00:00'),
        (100,   57, '2011-09-01 10:24:00'),
        (168,   68, '2012-07-13 12:10:06'),
        (207,   30,         '12012-12-05 12:12:00'),
        (112,   14, '2013-05-19 1:00:00');
        (177,   90, '2013-06-05 12:12:00'),
        (144,   56, '2013-06-19 1:00:00'),
        (168,   68,     '2013-07-13 12:10:06'),
        (119,   17, '2013-08-01 10:24:00'),
        (110,   10, '2013-08-05 12:12:00'),
        (113,   11, '2013-08-13 12:10:06'),
        (100,   57, '2013-09-01 10:24:00'),

添加新列后...我想要这样

仅自动手动插入PartitionID数据

(177,   90, '2010-06-05 12:12:00',156),
(144,   56, '2011-06-19 01:00:00',170),
(100,   57, '2011-09-01 10:24:00',244),
(168,   68, '2012-07-13 12:10:06',194),
(207, 30, '2012-12-05 12:12:00',340),
(112,   14, '2013-05-19 01:00:00',139),
(177,   90, '2013-06-05 12:12:00',156),
(144,   56, '2013-06-19 01:00:00',170),
(168,   68, '2013-07-13 12:10:06',194),
(119,   17, '2013-08-01 10:24:00',213),
(110,   10, '2013-08-05 12:12:00',217),
(113,   11, '2013-08-13 12:10:06',225),
(100,   57, '2013-09-01 10:24:00',244)

Answer 1

您无法为该列设置默认值，因为它是计算值，默认值必须是常量。但是您可以创建一个触发器来计算插入

上的值

delimiter |
CREATE TRIGGER PartitionIDtrigger BEFORE INSERT ON tmp
FOR EACH ROW 
BEGIN
    SET NEW.PartitionID = DAYOFYEAR(CURDATE());
END
|
delimiter ;

Answer 2

ALTER TABLE TestTable
ADD NewCol int
CONSTRAINT DF_TestTable_NewCol DEFAULT '1' NOT NULL
GO

我不确定这是否是您要找的，但这用于添加一个默认值为1的新列。

然后您可以创建一个TRIGGER，如@juergen所说，然后更改值。

如何自动添加数据

2 个答案: