单个表中的SQL时间差 [英] SQL time difference within single table

问题描述

我有一个具有用户登录数据的MySQL表。

 
 user |日期|类型
 ----- + --------------------- + ------ 
 1 | 2011-01-05 08:00:00 | login 
 1 | 2011-01-06 09:00:00 | login 
 1 | 2011-01-06 10:00:00 | logout 
 1 | 2011-01-06 09:50:00 |登录
 

鉴于上表，我想计算注销日期与上次登录日期之间的时间差，方法是添加一个新单元格持续时间。例如。退出日期为2011-01-06 10:00:00;并且先前的登录日期将为2011-01-06 09:50:00。

结果应该看起来像这样。 type = login的行不应有持续时间值。

 
 user |日期|类型|持续时间
 ----- + --------------------- + -------- + -------- -  
 1 | 2011-01-05 08:00:00 |登录| -  
 1 | 2011-01-06 09:00:00 |登录| -  
 1 | 2011-01-06 10:00:00 | logout | 10min 
 1 | 2011-01-06 09:50:00 |登录| -  
 

提前感谢

mawo

解决方案

  SELECT x。*，TIMEDIFF（x.logout_date，x.login_date）as duration 
 FROM 
 SELECT a.user_id，a.`date` as logout_date，
（SELECT MAX（b.`date`）FROM table1 b WHERE b.`date`< a.`date` 
 and b。 user = a.user和b.type ='login'）as login_date 
 FROM table1 a WHERE a.type ='logout'
）x 
  pre> 


I have a single MySQL table with login data of users.
user |  date               | type
-----+---------------------+------
1    | 2011-01-05 08:00:00 | login
1    | 2011-01-06 09:00:00 | login
1    | 2011-01-06 10:00:00 | logout
1    | 2011-01-06 09:50:00 | login
Given the above table I would like to calculate the time difference between the logout date and the previous login date by adding a new cell called duration. E.g. the logout date was '2011-01-06 10:00:00; and the previous login date would be '2011-01-06 09:50:00'. 

The result should look somehow like this. Rows with type=login should not have a duration value.
user |  date               | type   | duration
-----+---------------------+--------+----------
1    | 2011-01-05 08:00:00 | login  | -
1    | 2011-01-06 09:00:00 | login  | -
1    | 2011-01-06 10:00:00 | logout | 10min
1    | 2011-01-06 09:50:00 | login  | -
Thanks in advance,

mawo
解决方案
SELECT x.*, TIMEDIFF(x.logout_date, x.login_date) as duration
FROM
(
SELECT a.user_id, a.`date` as logout_date, 
(SELECT MAX(b.`date`) FROM table1 b WHERE b.`date` <a.`date` 
and b.user=a.user and b.type = 'login') as login_date    
FROM table1 a WHERE a.type ='logout'
)x


                        
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