Need Help in query

Started by Satish Burnwal (sburnwal)over 15 years ago3 messagesgeneral

sburnwal@cisco.com

over 15 years ago

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

Nicklas Avén

nicklas.aven@jordogskog.no

over 15 years ago

In reply to: Satish Burnwal (sburnwal) (#1)

Re: Need Help in query

Hallo

This I think should work.

To get the usernames by hour as you describe:

SELECT h.hour, usrlog.userid
(select generate_series(1,24) as hour) as h
inner join
usrlog
on h.hour >= usrlog.loginhr and h.hour <= usrlog.logouthr
order by h.hour, usrlog.userid;

To get the number of users per hour :

Select h.hour, count(*) asNumberOfUsers
(select generate_series(1,24) as hour) h
inner join
usrlog
on h.hour >= usrlog.loginhr and h.hour <= usrlog.logouthr
group by h.hour;

HTH

Nicklas

2010-12-23 skrev Satish Burnwal (sburnwal) :

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

Show quoted text

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

--
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general

Import Notes

Resolved by subject fallback

Satish Burnwal (sburnwal)

sburnwal@cisco.com

over 15 years ago

In reply to: Nicklas Avén (#2)

Re: Need Help in query

Thanks! I did not know such a function exists.

From: Nicklas Avén [mailto:nicklas.aven@jordogskog.no]
Sent: Thursday, December 23, 2010 3:31 PM
To: Satish Burnwal (sburnwal)
Cc: pgsql-general@postgresql.org
Subject: Re: [GENERAL] Need Help in query

Hallo

This I think should work.

To get the usernames by hour as you describe:

SELECT h.hour, usrlog.userid
(select generate_series(1,24) as hour) as h
inner join
usrlog
on h.hour >= usrlog.loginhr and h.hour <= usrlog.logouthr
order by h.hour, usrlog.userid;

To get the number of users per hour :

Select h.hour, count(*) asNumberOfUsers
(select generate_series(1,24) as hour) h
inner join
usrlog
on h.hour >= usrlog.loginhr and h.hour <= usrlog.logouthr
group by h.hour;

HTH

Nicklas

2010-12-23 skrev Satish Burnwal (sburnwal) :

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

Show quoted text

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

--
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general