借助算术运算符minus(-)更新datetime字段的日期。
语法如下update yourTableName
set yourDateTimeColumnName=yourDateTimeColumnName - interval yourValue day
where date(yourDateTimeColumnName)=’yourDateValue’;
为了理解上述语法,让我们创建一个表。创建表的查询如下mysql> create table updateDateDemo
-> (
-> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
-> ArrivalDate datetime
-> );
使用insert命令在表中插入一些记录。
查询如下mysql> insert into updateDateDemo(ArrivalDate) values('2011-01-13');
mysql> insert into updateDateDemo(ArrivalDate) values('2013-04-21');
mysql> insert into updateDateDemo(ArrivalDate) values('2016-12-22');
mysql> insert into updateDateDemo(ArrivalDate) values('2017-02-25');
mysql> insert into updateDateDemo(ArrivalDate) values('2018-08-19');
mysql> insert into updateDateDemo(ArrivalDate) values('2019-02-27');
使用select语句显示表中的所有记录。
查询如下mysql> select *from updateDateDemo;
以下是输出+----+---------------------+
| Id | ArrivalDate |
+----+---------------------+
| 1 | 2011-01-13 00:00:00 |
| 2 | 2013-04-21 00:00:00 |
| 3 | 2016-12-22 00:00:00 |
| 4 | 2017-02-25 00:00:00 |
| 5 | 2018-08-19 00:00:00 |
| 6 | 2019-02-27 00:00:00 |
+----+---------------------+
6 rows in set (0.00 sec)
这是更新日期时间字段的日期的查询mysql> update updateDateDemo
-> set ArrivalDate=ArrivalDate-interval 7 day
-> where date(ArrivalDate)='2019-02-27';
Rows matched: 1 Changed: 1 Warnings: 0
现在从表中检查更新的记录mysql> select *from updateDateDemo;
以下是输出+----+---------------------+
| Id | ArrivalDate |
+----+---------------------+
| 1 | 2011-01-13 00:00:00 |
| 2 | 2013-04-21 00:00:00 |
| 3 | 2016-12-22 00:00:00 |
| 4 | 2017-02-25 00:00:00 |
| 5 | 2018-08-19 00:00:00 |
| 6 | 2019-02-20 00:00:00 |
+----+---------------------+
6 rows in set (0.00 sec)