There is no need to record sessionid. Do you want to use sessionid to record the last operation time of abnormal exit?
The last piece of data logged in by the same user must be a logout operation
1. Normal logout, the next piece of data must be a login
2. After normal operations (add, delete, modify, check) and abnormal shutdown, the next time it must be a login operation

So the length of a login time is the current login time - the time of the previous record before the next login

However, if the user does not log in after abnormal shutdown, it needs to be processed separately. For example, the sessionid will expire if there is no operation for 20 minutes. Just check whether the last record is more than 20 minutes ago. If it is more than 20 minutes ago, it will be considered as an abnormal exit.

Anyway, there must be user identification to determine which user’s behavior log it is,

When writing the log, write the time difference between each login and logout into the log, and add it up at the end?

The table can be designed like this

用户id   登录时间  退出时间

When logging in, the login time is recorded in the session, and the exit time is set to: login time + timeout time.

When the user is active, based on the login time recorded in the session, the exit time of that record is updated: current time + timeout time.

When exiting, according to the login time recorded in the session, the exit time of that record is updated to: the current time.

Original table (assumed):

record_id    uid    name      opr_type    c_time
1            10     cxl       land        2016-12-26 08:00:00
2            10     cxl       out         2016-12-26 23:00:00

The final generated table:

用户名    日期（asc）    当天第一次登陆时间     当天最后一次登出时间     登陆时长（结果非准确值）
cxl      2016-12-26    2016-12-26 08:00:00  2016-12-26 15:00:00   3小时10分
cxl      2016-12-27    2016-12-26 08:30:00  2016-12-26 23:00:00   6小时10分

Detailed process:

1. 日期分组
2. 当天第一次登陆时间
     2.1 第一种情况：若当天第一条记录操作类型是 登出，那么 当天第一次登陆时间 = 00:00:01
     2.2 第二种情况：若当天第一条记录操作类型是 登陆，那么 当天第一次登陆时间 = c_time
    
3. 当天最后一次登出时间
    3.1 第一种情况：若当天最后一条记录操作类型是 登陆，那么 当天最后一次登出时间 = 23:59:59
    3.2 第二种情况：若当天最后一条记录操作类型是 登出，那么 当天最后一次登出时间 = c_time
4. 登陆时长 
    4.1 当天最后一次登出时间 - 当天第一次登陆时间

Give me some ideas. I personally think it is not easy to implement. (Logic processing requires PHP, and paging is also troublesome. It has to be displayed in paging according to the date, instead of paging according to the number of records taken out like limit 1 , 10. Single paging sql cannot derive the final table structure), so we can only go here....

Can I ask everyone a question? Login can be recorded, but how to record logout? The user may not actually click the logout button. If it is the web, the user can just close the browser and leave it alone. How do you know when you logged out? session?