MySQL 使用 DATEDIFF 查询

Question

我正在尝试构建一个查询，该查询将比较 2 个字段 - start_time 和 end_date.

从特定日期加载记录到特定日期

SELECT start_time
,end_time
,DATEDIFF(end_time, start_time) AS DiffDate
FROM my_tbl
WHERE start_time >= '2015-04-27 00:00:00'
AND end_time <= '2015-04-28 00:00:00'
AND end_time >= '2015-04-27 00:00:00'
AND DiffDate < 100
LIMIT 1000;

不幸的是 DiffDate returns 总是 0。理想的情况是在插入 end_time 时计算 start_time 和 end_time 之间的差异，但我无法对数据库进行任何更改。我在这里做错了什么？即使 DiffDate 在工作，它会被认为是一个好的解决方案吗？

Answer 1

来自 MS SQL 我使用的是 DATEDIFF 但解决方案是：

SELECT start_time
,end_time
,TIMESTAMPDIFF(SECOND,start_time,end_time) AS DiffDate
FROM my_tbl
WHERE start_time >= '2015-04-27 00:00:00'
AND end_time <= '2015-04-28 00:00:00'
AND end_time >= '2015-04-27 00:00:00'
AND DiffDate < 100
LIMIT 1000;

我想知道是否有更好的解决方案。

Answer 2

Start_time and end_time are datetime column. So use TimeDIFF..

SELECT start_time, end_time, TIMEDIFF(end_time, start_time) AS DiffDate
FROM my_tbl
WHERE start_time >= '2015-04-27 00:00:00'
AND end_time <= '2015-04-28 00:00:00'
AND end_time >= '2015-04-27 00:00:00'
AND DiffDate < 100
LIMIT 1000;

Answer 3

从 where 子句中的条件看来，您正在尝试获取同一日期的数据，但是在同一天使用 datediff 总是会得到 0

mysql> select datediff('2015-04-27 12:00:00','2015-04-27 00:00:00') as diff ;
+------+
| diff |
+------+
|    0 |
+------+

1 row in set (0.03 sec)

您可能需要其他计算方式，例如使用 timestampdiff

mysql> select timestampdiff(minute ,'2015-04-27 00:00:00','2015-04-27 12:00:00') as diff ;
+------+
| diff |
+------+
|  720 |
+------+
1 row in set (0.00 sec)

您还在 where 子句中使用别名，这是不允许的，您必须将其更改为 having 子句

SELECT start_time
,end_time
,timestampdiff(minute,start_time,end_time) AS DiffDate
FROM my_tbl
WHERE start_time >= '2015-04-27 00:00:00'
AND end_time <= '2015-04-28 00:00:00'
AND end_time >= '2015-04-27 00:00:00'
having DiffDate < 100
LIMIT 1000;

Answer 4

SELECT start_time,end_time,DATEDIFF(end_time, start_time) AS DiffDate FROM my_tbl WHERE start_time >= '2015-04-27 00:00:00' AND end_time between '2015-04-27 00:00:00' AND '2015-04-28 00:00:00' AND for date diff < 100 LIMIT 1000;

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