Обсуждение: look for latest user login in one table from a list of users in a nother

I'm trying to come up with an efficient way to do the following task, but I
haven't found the correct join syntax to do it.

I have table "users" for keeping a list of users I need to check logins for.
It contains the following fields:

id,Full-Name,User-Name

I have table called "logs" that contains the actual radius log data.  The
three fields I am concerned with are:

User-Name,Date,Time

I have gotten thus far almost what I want with the following query.

SELECT users."User-Name",max(logs."Date") as login_date,max(logs."Time") as
login_time FROM logs where logs."User-Name"=users."User-Name" GROUP BY
users."User-Name";

This gives me the User-Name, date, and time of people WHO HAVE LOGGED IN.
I'm looking to have a query that returns all of the users in the first
table, including those who have not logged in.  I have an external perl
script that generates a nice html report for the manager.  I have a script
that parses the raw .csv files, but I'm trying to move it entirely to
postgres, including if possible stored-procedures in plperl.  I already have
a perl script that imports the raw log files into the logs table.

Am I on the right track?

Thanks,

Stephen Sill II

On Fri, 14 Mar 2003, Sill-II, Stephen wrote:

> I'm trying to come up with an efficient way to do the following task, but I
> haven't found the correct join syntax to do it.
> 
> I have table "users" for keeping a list of users I need to check logins for.
> It contains the following fields:
> 
> id,Full-Name,User-Name
> 
> I have table called "logs" that contains the actual radius log data.  The
> three fields I am concerned with are:
> 
> User-Name,Date,Time
> 
> I have gotten thus far almost what I want with the following query.
> 
> SELECT users."User-Name",max(logs."Date") as login_date,max(logs."Time") as
> login_time FROM logs where logs."User-Name"=users."User-Name" GROUP BY
> users."User-Name";

Try
foo=# SELECT users.name,someq.mlast from users left outer join (select 
id,max(last) as mlast from log group by id) as someq using(id);

substituting with your names.

> 
> This gives me the User-Name, date, and time of people WHO HAVE LOGGED IN.
> I'm looking to have a query that returns all of the users in the first
> table, including those who have not logged in.  I have an external perl
> script that generates a nice html report for the manager.  I have a script
> that parses the raw .csv files, but I'm trying to move it entirely to
> postgres, including if possible stored-procedures in plperl.  I already have
> a perl script that imports the raw log files into the logs table.
> 
> Am I on the right track?
> 
> Thanks,
> 
> Stephen Sill II
> 
> 
> 
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> 
> http://archives.postgresql.org
> 

-- 
==================================================================
Achilleus Mantzios
S/W Engineer
IT dept
Dynacom Tankers Mngmt
Nikis 4, Glyfada
Athens 16610
Greece
tel:    +30-210-8981112
fax:    +30-210-8981877
email:  achill@matrix.gatewaynet.com       mantzios@softlab.ece.ntua.gr

Try:

select users."User-Name", ss."Date", ss."Time" from users left outer
join ( select distinct on ("User-Name") "User-Name", "Date", "Time" order by
1, 2 DESC, 3 DESC) as sson ( users."User-Name" = ss."User-Name")
order by 1;

It help if yo uhave an index on logs( "User-Name", "Date" desc, "Time"
desc).

JL

PS Can't you convert "Date" || "Time"  to timestamp?


"Sill-II, Stephen" wrote:
> 
> I'm trying to come up with an efficient way to do the following task, but I
> haven't found the correct join syntax to do it.
> 
> I have table "users" for keeping a list of users I need to check logins for.
> It contains the following fields:
> 
> id,Full-Name,User-Name
> 
> I have table called "logs" that contains the actual radius log data.  The
> three fields I am concerned with are:
> 
> User-Name,Date,Time
> 
> I have gotten thus far almost what I want with the following query.
> 
> SELECT users."User-Name",max(logs."Date") as login_date,max(logs."Time") as
> login_time FROM logs where logs."User-Name"=users."User-Name" GROUP BY
> users."User-Name";
> 
> This gives me the User-Name, date, and time of people WHO HAVE LOGGED IN.
> I'm looking to have a query that returns all of the users in the first
> table, including those who have not logged in.  I have an external perl
> script that generates a nice html report for the manager.  I have a script
> that parses the raw .csv files, but I'm trying to move it entirely to
> postgres, including if possible stored-procedures in plperl.  I already have
> a perl script that imports the raw log files into the logs table.
> 
> Am I on the right track?
> 
> Thanks,
> 
> Stephen Sill II
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?
> 
> http://archives.postgresql.org