Amit,
You say "I want to know how much time it took for a bill to be
accepted after it was submitted"
So, do you want between 10 and 40, not 10 and 20?
I assume you meant 10 and 40.
Ok, there's a few approaches to your questions, first
To get "how much time it took for a bill to be accepted after
it was submitted":
select bill_id,
(max(case when status_id = 40
then statustime end) -
max(case when status_id = 10
then statustime end))
from bill_status
where status_id in ( 10,40 )
group by bill_id;
that will give you the amt of time (simple date arithmetic, so, in days)
from submission to being accepted.
You also, want a simple distribution, you can use the technique above
But with SUM:
select sum(case when diff < 7 then 1 else 0 end) as lt_7,
sum(case when diff between 7 and 15 then 1 else 0 end) as
btw_7_15,
sum(case when diff > 15 then 1 else 0 end) as gt_15
from (
select bill_id,
(max(case when status_id = 40
then statustime end) -
max(case when status_id = 10
then statustime end)) as diff
from bill_status
where status_id in ( 10,40 )
group by bill_id
) x;
I have a recipe in my upcoming book ('The SQL Cookbook' by O'Reilly)
So, I'd like to know if what I suggested works out for you.
Obviously, you'll need whatever tweaks to make it perfect for your
system, the feedback I am concerned about is the technique.
hope that helps,
Anthony
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
[EMAIL PROTECTED]
Sent: Tuesday, August 30, 2005 5:45 AM
To: pgsql-sql@postgresql.org
Subject: [SQL] Time differences between rows, not columns?
Importance: High
Using postgresSQL 8.0 for windows, running on windows 2003 server 16gb
RAM, 3Ghz dual p4.
Language: Java - JDBC postgres driver: postgresql-8.0-310.jdbc3.jar
I have an application with 3 tables (in this context that is)
Table bills
bill_id NOT NULL serial
... And other columns
Table bill_status
bill_id (references bills.bill_id)
statusid int4 (references bill_statuslookup.statusid)
statustime datetime
Table bill_statuslookup
statusid serial not null
statusname varchar(255)
The application basically tracks a workflow of bills flowing fromone
department to another.
Everytime the bill moves one step, an entry is made into the bill_status
table.
Eg.
Bills table
-------------
Bill_id otherfield1
1 ........
Bill_status table:
---------------------
Bill_id statusid statustime
1 10 2005-04-04 00:34:31
1 20 2005-04-05 00:55:00
Bill_statuslookup table:
-------------------------
Statusid Statusname
10 submitted
20 received
30 rejected
40 accepted
..
..
Now my problem is this:
1. Find the time taken for each bill to reach from status 10 to status
20 , given the time of status 10 should be between t1 and t2.
Eg I want to know how much time it took for a bill to be accepted after
it was submitted (criteria: submitted between yesterday and today)
2. I want to know how many bills took <7 days, how many tok 7-15 days,
how many took >15 days etc.
The status is a lookup table because the workflow constantly changes,
and I can't have submitted_on, recd_on accepted_on times etc in the main
bills table as columns because there are way too many statuses in the
life of a bill (read invoice).
Hope its clear as to what I'm looking for.
Any help is greatly appreciated!!
Regards,
Amit
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