I need a help in writing a query. I have data as follows:

mydb=# select * from usrlog ;
 logid |  userid  | loginhr | logouthr 
-------+----------+---------+----------
     0 | sburnwal |       0 |        1
     1 | rickyrs   |       1 |        5
     2 | satishbn |       1 |        6
     3 | taohujin |       2 |        4
     4 | jospehm |       4 |        5


Table captures the login and logout time (taking hour here to simplify)
of users and my aim to find the number of logged-in users (online users)
at every hr (1st hr i.e. 0-1, 2nd hrs i.e. 1-2, 3rd hr i.e. 2-3 and ...
so on). As the data indicates, use is not logging out in same hr as hr
of login. A user can be logged-in for more than one hr. For example,
here user rickyrs is logged-in for 1st, 2nd, 3rd, 4th  and 5th hr. My
query needs to find out in the last 24 hrs, how many users were
logged-in at each hr. I want the result this way:

Nth-hr           user
---------------------------
1               sburnwal
2               rickyrs
2               satishbn
3               rickyrs
3               satishbn
3               taohujin
4               rickyrs
4               satishbn
4               taohujin
4               josephm

Appreciate your response in advance. For me, even the count of users on
hourly basis is fine.

Thanks
-Satish

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