添加DATE和TIME字段以在MySQL中获取DATETIME字段？

您可以使用CONCAT()函数设置日期和时间字段以获取DATETIME字段。

让我们创建一个演示表

mysql> create table getDateTimeFieldsDemo
   -> (
   -> ShippingDate date,
   -> ShippingTime time,
   -> Shippingdatetime datetime
   -> );

使用insert命令在表中插入一些记录。查询如下-

mysql> insert into getDateTimeFieldsDemo(ShippingDate,ShippingTime) values('2018-01-21','09:45:34');
mysql> insert into getDateTimeFieldsDemo(ShippingDate,ShippingTime) values('2013-07-26','13:21:20');
mysql> insert into getDateTimeFieldsDemo(ShippingDate,ShippingTime) values('2017-12-31','15:31:40');
mysql> insert into getDateTimeFieldsDemo(ShippingDate,ShippingTime) values('2019-03-07','12:13:34');

使用select语句显示表中的所有记录。查询如下-

mysql> select *from getDateTimeFieldsDemo;

以下是输出

+--------------+--------------+------------------+
| ShippingDate | ShippingTime | Shippingdatetime |
+--------------+--------------+------------------+
| 2018-01-21   | 09:45:34     | NULL             |
| 2013-07-26   | 13:21:20     | NULL             |
| 2017-12-31   | 15:31:40     | NULL             |
| 2019-03-07   | 12:13:34     | NULL             |
+--------------+--------------+------------------+
4 rows in set (0.00 sec)

这是添加DATE和TIME字段以在MySQL中获取DATETIME字段的查询

mysql> update getDateTimeFieldsDemo set Shippingdatetime=concat(ShippingDate," ",ShippingTime);
Rows matched: 4 Changed: 4 Warnings: 0

现在再次检查表记录。查询如下-

mysql> select *from getDateTimeFieldsDemo;

以下是输出

+--------------+--------------+---------------------+
| ShippingDate | ShippingTime | Shippingdatetime    |
+--------------+--------------+---------------------+
| 2018-01-21   | 09:45:34     | 2018-01-21 09:45:34 |
| 2013-07-26   | 13:21:20     | 2013-07-26 13:21:20 |
| 2017-12-31   | 15:31:40     | 2017-12-31 15:31:40 |
| 2019-03-07   | 12:13:34     | 2019-03-07 12:13:34 |
+--------------+--------------+---------------------+
4 rows in set (0.00 sec)