我在5.6版本中使用MySQL。 (提及因为不存在可用的mysql函数)
给出一个表"运动检测"时间戳。每行检测到一个动作。没有动议意味着没有进入。
Id | Date Time
---------------
1 | 2018-01-01 15:00:01 // Start of activity phase 1
2 | 2018-01-01 15:00:03
3 | 2018-01-01 15:00:06 // Stop of activity phase 1
// Non-Activity phase
4 | 2018-01-01 17:01:06 // Start of activity phase 2
5 | 2018-01-01 17:02:06
6 | 2018-01-01 17:02:09 // Stop of activity phase 2
// Non-Activity phase, big one because of holiday
7 | 2018-01-10 19:40:06 // Start of activity phase 3
8 | 2018-01-10 19:41:06 // Stop of activity phase 3
我很难找到一个SQL查询来概述" 活动阶段"。
我试图得到的是:
Id | Activity starts | Activity ends
---------------------------------------------
1 | 2018-01-01 15:00:01 | 2018-01-01 15:00:06
2 | 2018-01-01 17:01:06 | 2018-01-01 17:02:09
3 | 2018-01-10 19:40:06 | 2018-01-10 19:41:06
我希望看到" 活动阶段"的开始和结束时间戳。 定义" 活动阶段":" 活动阶段"位于两个" 非活动阶段" (例如)至少30分钟。
提前谢谢你。
答案 0 :(得分:1)
我认为在MySQL 5.6中实现这一目标的唯一方法是使用存储过程(尽管我很乐意看到有人证明我错了)。这个会做你想要的。请注意,它返回了许多单行结果集,因此您需要在应用程序框架中处理它。或者,您可以修改过程以将中间结果存储到临时表中,然后在过程结束时修改临时表中的SELECT
所有内容(参见下文)。
DELIMITER //
DROP PROCEDURE IF EXISTS get_activity //
CREATE PROCEDURE get_activity()
BEGIN
DECLARE start, thistime, lasttime DATETIME;
DECLARE activity_count INT DEFAULT 1;
DECLARE finished INT DEFAULT 0;
DECLARE activity_cursor CURSOR FOR SELECT atime FROM activity;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET finished = 1;
OPEN activity_cursor;
FETCH activity_cursor INTO start;
SET lasttime = start;
act_loop: LOOP
FETCH activity_cursor INTO thistime;
IF finished = 1 THEN
SELECT activity_count, start, lasttime AS end;
LEAVE act_loop;
END IF;
IF thistime > lasttime + INTERVAL 30 MINUTE THEN
SELECT activity_count, start, lasttime AS end;
SET start = thistime;
SET activity_count = activity_count + 1;
END IF;
SET lasttime = thistime;
END LOOP;
END //
对于您的样本数据,此过程返回:
activity_count start end
1 2018-01-01 15:00:01 2018-01-01 15:00:06
activity_count start end
2 2018-01-01 17:01:06 2018-01-01 17:02:09
activity_count start end
3 2018-01-10 19:40:06 2018-01-10 19:41:06
这是临时表的过程:
DELIMITER //
DROP PROCEDURE IF EXISTS get_activity //
CREATE PROCEDURE get_activity()
BEGIN
DECLARE start, thistime, lasttime DATETIME;
DECLARE activity_count INT DEFAULT 1;
DECLARE finished INT DEFAULT 0;
DECLARE activity_cursor CURSOR FOR SELECT atime FROM activity;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET finished = 1;
CREATE TEMPORARY TABLE activity_temp (id INT, start DATETIME, end DATETIME);
OPEN activity_cursor;
FETCH activity_cursor INTO start;
SET lasttime = start;
act_loop: LOOP
FETCH activity_cursor INTO thistime;
IF finished = 1 THEN
INSERT INTO activity_temp VALUES (activity_count, start, lasttime);
LEAVE act_loop;
END IF;
IF thistime > lasttime + INTERVAL 30 MINUTE THEN
INSERT INTO activity_temp VALUES (activity_count, start, lasttime);
SET start = thistime;
SET activity_count = activity_count + 1;
END IF;
SET lasttime = thistime;
END LOOP;
SELECT * FROM activity_temp;
DROP TABLE activity_temp;
END //
输出(来自CALL get_activity()
):
id start end
1 2018-01-01 15:00:01 2018-01-01 15:00:06
2 2018-01-01 17:01:06 2018-01-01 17:02:09
3 2018-01-10 19:40:06 2018-01-10 19:41:06
答案 1 :(得分:0)
尽管@Nick提供了合适的答案,但我花了几个小时才找到以下解决方案:
SET @row_number = 0;
SET @row_number2 = 0;
SET @gap_time = "00:30:00";
Select
"",
DAYNAME(prep1.datetime2) "Weekday",
prep1.datetime2 "Activity starts",
prep2.datetime1 "Activity ends"
FROM
(SELECT
(@row_number:=@row_number + 1) AS num
,detection1.id id1
,detection1.insert_datetime datetime1
,detection2.id id2
,detection2.insert_datetime datetime2
,timediff(detection2.insert_datetime,detection1.insert_datetime) as diff
FROM
MOVEMENT_TRACKING detection1,
MOVEMENT_TRACKING detection2
WHERE
detection1.id + 1 = detection2.id
and timediff(detection2.insert_datetime,detection1.insert_datetime) > @gap_time
order by detection1.id) as prep1,
(SELECT
(@row_number2:=@row_number2 + 1) AS num
,detection1.id id1
,detection1.insert_datetime datetime1
,detection2.id id2
,detection2.insert_datetime datetime2
,timediff(detection2.insert_datetime,detection1.insert_datetime) as diff
FROM
MOVEMENT_TRACKING detection1,
MOVEMENT_TRACKING detection2
WHERE
detection1.id + 1 = detection2.id
and timediff(detection2.insert_datetime,detection1.insert_datetime) > @gap_time
order by detection1.id) as prep2
WHERE
prep1.num + 1 = prep2.num
ORDER BY
prep1.datetime2 DESC
仍然可以进行一些减少,因为调试原因我让它们进入。有些黑客需要像
一样Select ""
因为数据库托管安全警察规则。