只比较 MySQL 日期字段中的「日」和「月」?
借助 DATE_FORMAT(),你只能比较 MySQL 日期字段中的「日」和「月」。
语法如下:
select *from yourTableName
WHERE DATE_FORMAT(yourColumnName, '%m-%d') = DATE_FORMAT('yourValue', '%m-%d') and yourCondition;为了理解上述语法,我们创建一个表。创建表的查询如下:
mysql> create table compareDayAndMonthDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> compareDayAndTime date -> ); Query OK, 0 rows affected (0.49 sec)
使用 insert 命令向表中插入一些记录。
查询如下:
mysql> insert into compareDayAndMonthDemo(compareDayAndTime) values('2014-01-31');
Query OK, 1 row affected (0.20 sec)
mysql> insert into compareDayAndMonthDemo(compareDayAndTime) values('2014-10-11');
Query OK, 1 row affected (0.16 sec)
mysql> insert into compareDayAndMonthDemo(compareDayAndTime) values('2016-09-12');
Query OK, 1 row affected (0.08 sec)
mysql> insert into compareDayAndMonthDemo(compareDayAndTime) values('2017-04-25');
Query OK, 1 row affected (0.08 sec)
mysql> insert into compareDayAndMonthDemo(compareDayAndTime) values('2018-12-25');
Query OK, 1 row affected (0.08 sec)
mysql> insert into compareDayAndMonthDemo(compareDayAndTime) values('2019-02-27');
Query OK, 1 row affected (0.07 sec)使用 select 语句从表中显示所有记录。
查询如下:
mysql> select *from compareDayAndMonthDemo;
输出如下:
+----+-------------------+ | Id | compareDayAndTime | +----+-------------------+ | 1 | 2014-01-31 | | 2 | 2014-10-11 | | 3 | 2016-09-12 | | 4 | 2017-04-25 | | 5 | 2018-12-25 | | 6 | 2019-02-27 | +----+-------------------+ 6 rows in set (0.00 sec)
以下是如何仅比较「日」和「月」的查询:
mysql> select *from compareDayAndMonthDemo
-> WHERE DATE_FORMAT(compareDayAndTime, '%m-%d') = DATE_FORMAT('2019-01-31', '%m-%d') and Id=1;输出如下:
+----+-------------------+ | Id | compareDayAndTime | +----+-------------------+ | 1 | 2014-01-31 | +----+-------------------+ 1 row in set (0.00 sec)
如果你只需要「日」和「月」,请使用以下查询:
mysql> select DATE_FORMAT(compareDayAndTime, '%m-%d') AS DayAndMonthOnly from compareDayAndMonthDemo
-> WHERE DATE_FORMAT(compareDayAndTime, '%m-%d') = DATE_FORMAT('2019-01-31', '%m-%d') and Id=1;输出如下:
+-----------------+ | DayAndMonthOnly | +-----------------+ | 01-31 | +-----------------+ 1 row in set (0.00 sec)
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