Question

我正在尝试返回在过去10秒内创建的所有行，即“date_created”＆lt; 10秒钟。这是我正在使用的sql，但这似乎不起作用：

SELECT COUNT(amount) FROM tablename WHERE date_created>= DATE_SUB(NOW(), INTERVAL 10 SECOND)

......任何人都可以帮助我吗？

非常感谢。

Answer 1

确保将date_created列设置为TIMESTAMP而不是DATETIME - 否则计算将无法正常工作。

漫长的一天。

感谢您的帮助。

Answer 2

您的查询中唯一的缺陷是它将来会返回元素：

mysql> create table tablename(
    ->  date_created datetime
    -> );
Query OK, 0 rows affected (0.01 sec)

mysql>
mysql> insert into tablename (date_created) values
    -> ('2000-02-29 15:00:00'),
    -> (CURRENT_TIMESTAMP),
    -> (CURRENT_TIMESTAMP - interval 5 second),
    -> (CURRENT_TIMESTAMP - interval 11 second),
    -> ('2022-08-14 12:00:00');
Query OK, 5 rows affected (0.01 sec)
Records: 5  Duplicates: 0  Warnings: 0

mysql>
mysql> select date_created,
    -> case
    ->   when date_created>= DATE_SUB(NOW(), INTERVAL 10 SECOND)
    ->   then 'Matches'
    ->   else 'Does not match'
    -> end as 'Match'
    -> from tablename;
+---------------------+----------------+
| date_created        | Match          |
+---------------------+----------------+
| 2000-02-29 15:00:00 | Does not match |
| 2015-11-06 11:44:17 | Matches        |
| 2015-11-06 11:44:12 | Matches        |
| 2015-11-06 11:44:06 | Does not match |
| 2022-08-14 12:00:00 | Matches        | <==== This is not correct
+---------------------+----------------+
5 rows in set (0.00 sec)

只需附加相应的限制：

AND date_created<=NOW()

MYSQL DATE_SUB无法正常工作

2 个答案: