从 MySQL 中具有 DATE 和 NULL 记录的表中过滤日期
mysqlmysqli database更新于 2025/12/12 2:20:17
首先我们创建一个表 −
mysql> create table DemoTable ( FirstDate datetime, SecondDate datetime ); Query OK, 0 rows affected (0.57 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable values('2019-01-21','2018-01-21');
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable values('2019-10-04','2019-08-14');
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable values('2019-05-01','2019-09-11');
Query OK, 1 row affected (0.65 sec)
mysql> insert into DemoTable values(NULL,NULL);
Query OK, 1 row affected (0.18 sec)
mysql> insert into DemoTable values('2019-03-01',NULL);
Query OK, 1 row affected (0.13 sec)
使用 select 语句显示表中的所有记录 −
Display all records from the table using select statement:
这将产生以下输出 −
+---------------------+---------------------+ | FirstDate | SecondDate | +---------------------+---------------------+ | 2019-01-21 00:00:00 | 2018-01-21 00:00:00 | | 2019-10-04 00:00:00 | 2019-08-14 00:00:00 | | 2019-05-01 00:00:00 | 2019-09-11 00:00:00 | | NULL | NULL | | 2019-03-01 00:00:00 | NULL | +---------------------+---------------------+ 5 rows in set (0.00 sec)
以下是从包含 DATE 和 NULL 记录的表中过滤日期的查询 −
mysql> select *from DemoTable where FirstDate <= curdate() and (SecondDate >=curdate() or SecondDate IS NULL);
这将产生以下输出 −
+---------------------+---------------------+ | FirstDate | SecondDate | +---------------------+---------------------+ | 2019-05-01 00:00:00 | 2019-09-11 00:00:00 | | 2019-03-01 00:00:00 | NULL | +---------------------+---------------------+ 2 rows in set (0.00 sec)
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