Crosstab query

Posted on 2003-10-22
Medium Priority
Last Modified: 2008-07-03
I need to create a query that will show the last N months of data for each person in the database.  Here's a simplied version of what my table would look like:

create table test_table (
      personid int,
      value int,
      cdate date)

personid value cdate
-------- ----- ----------
1        100   08/01/2003
1        200   09/01/2003
1        300   10/01/2003
2        400   08/01/2003
2        500   09/01/2003
2        600   10/01/2003

Let's say that I just want to show the last 3 months of data.  Here's what I would like the query to return:

personid  08-2003   09-2003   10-2003
--------  -------   -------   -------
1         100       200       300
2         400       500       600

I actually don't even need the columns to read like shown.  They could be like this:

personid  date1     date2     date3
--------  -----     -----     -----

Anyone have any ideas???

Question by:jgaull
LVL 33

Expert Comment

ID: 9600287
select d0.personid, d0.value as date0_value , d1.value as date1_value, d2.value as date2_value

from test_table d0
join ( select personid, value from test_table where cdate=today()-1 month ) d1
on d1.personid=d0.personid
join ( select personid, value from test_table where cdate=today()-2 month ) d2
on d0.personid=d2.personid

LVL 50

Accepted Solution

Lowfatspread earned 2000 total points
ID: 9615571
this is the general format for a pivot query...

use group by
and an aggregation function in the select   e.g. Min,max,sum, ....
with a case statement inside the brackets to identify when the value should be "exposed" for
that column...)    

sum(case when month(cdate) = month(current date) and year(cdate)  = year(current date) then value else null end) as Current
,sum(case when month(cdate) = month(current date - 1 month)  and year(cdate)  = year(current date - 1 month) then value else null end) as lastMonth
,sum(case when month(cdate) = month(current date - 2 month)  and year(cdate)  = year(current date - 2 month) then value else null end) as "2Monthsago"
from test_table
group by personid


Featured Post

Get expert help—faster!

Need expert help—fast? Use the Help Bell for personalized assistance getting answers to your important questions.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

November 2009 Recently, a question came up in the DB2 forum regarding the date format in DB2 UDB for AS/400.  Apparently in UDB LUW (Linux/Unix/Windows), the date format is a system-wide setting, and is not controlled at the session level.  I'm n…
Recursive SQL in UDB/LUW (it really isn't that hard to do) Recursive SQL is most often used to convert columns to rows or rows to columns.  A previous article described the process of converting rows to columns.  This article will build off of th…
Free Data Recovery software is an advanced solution from Kernel Tools to recover data and files such as documents, emails, database, media and pictures, etc. It supports recovery from physical & logical drive after a hard disk crash, accidental/inte…
From store locators to asset tracking and route optimization, learn how leading companies are using Google Maps APIs throughout the customer journey to increase checkout conversions, boost user engagement, and optimize order fulfillment. Powered …

587 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question