Update Previous Price for datatable

I have a table
ModelID,
Code,
BusDate,
Price
PrevPrice


I need to update the PrevPrice by getting the Price value for a given ModelID, Code from the previous BusDate.

The tables primary key is ModelID, Code, BusDate

Example
ModelID, Code, BusDate ,     Price,   PrevPrice
1 ,            'ABX', 10/18/2013 ,  7.00  ,   0
1 ,            'ABX', 10/18/2013 ,  9.00  ,   0
1 ,            'ABX', 10/21/2013 ,  10.00 ,   0
1 ,            'ABX', 10/22/2013 ,  8.00  ,   0

In the above example I would the data after the update statement to be
1 ,            'ABX', 10/18/2013 ,  7.00  ,   0
1 ,            'ABX', 10/18/2013 ,  9.00  ,   7.00
1 ,            'ABX', 10/21/2013 ,  10.00 ,   9.00
1 ,            'ABX', 10/22/2013 ,  8.00  ,   10.00
LVL 1
countrymeisterAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

awking00Information Technology SpecialistCommented:
Can we assume a time value is present for the busdate? Otherwise, how would you distinguish
1 ,            'ABX', 10/18/2013 ,  7.00  ,   0
1 ,            'ABX', 10/18/2013 ,  9.00  ,   7.00
from
1 ,            'ABX', 10/18/2013 ,  9.00  ,   0
1 ,            'ABX', 10/18/2013 ,  7.00  ,   9.00
?
0
countrymeisterAuthor Commented:
Sorry, my example should have had the following, since ModelID, Code and BusDate are the primary key

ModelID, Code, BusDate ,     Price,   PrevPrice
1 ,            'ABX', 10/17/2013 ,  7.00  ,   0
1 ,            'ABX', 10/18/2013 ,  9.00  ,   0
1 ,            'ABX', 10/21/2013 ,  10.00 ,   0
1 ,            'ABX', 10/22/2013 ,  8.00  ,   0

In the above example I would the data after the update statement to be
1 ,            'ABX', 10/17/2013 ,  7.00  ,   0
1 ,            'ABX', 10/18/2013 ,  9.00  ,   7.00
1 ,            'ABX', 10/21/2013 ,  10.00 ,   9.00
1 ,            'ABX', 10/22/2013 ,  8.00  ,   10.00
0
awking00Information Technology SpecialistCommented:
SQL> select * from yourtable;
   MODELID COD BUSDATE        PRICE  PREVPRICE
---------- --- --------- ---------- ----------
         1 ABX 17-OCT-13          7          0
         1 ABX 18-OCT-13          9          0
         1 ABX 21-OCT-13         10          0
         1 ABX 22-OCT-13          8          0

SQL> merge into yourtable y
  2  using
  3  (select modelid, code, busdate, price,
  4   lag(price) over (partition by modelid, code order by busdate) prevprice
  5   from yourtable) x
  6  on (y.modelid = x.modelid and y.code = x.code and y.busdate = x.busdate)
  7  when matched then
  8  update set y.prevprice = nvl(x.prevprice,0);

4 rows merged.
SQL> select * from yourtable;
   MODELID COD BUSDATE        PRICE  PREVPRICE
---------- --- --------- ---------- ----------
         1 ABX 17-OCT-13          7          0
         1 ABX 18-OCT-13          9          7
         1 ABX 21-OCT-13         10          9
         1 ABX 22-OCT-13          8         10
0
Big Business Goals? Which KPIs Will Help You

The most successful MSPs rely on metrics – known as key performance indicators (KPIs) – for making informed decisions that help their businesses thrive, rather than just survive. This eBook provides an overview of the most important KPIs used by top MSPs.

countrymeisterAuthor Commented:
I cannot use lag as it is a 2012 function. I am using sql 2008
0
awking00Information Technology SpecialistCommented:
Try this -
merge into yourtable a
using
(select x.modelid, x.code, x.busdate, x.price, nvl(y.price,0) as prevprice from
 (select modelid, code, busdate, price,
  row_number() over (partition by modelid, code order by busdate) rn
  from yourtable) x left join
 (select modelid, code, busdate, price,
  row_number() over (partition by modelid, code order by busdate) rn
  from yourtable) y
 on y.rn = x.rn - 1) z
on (a.modelid = z.modelid and a.code = z.code and a.busdate = z.busdate)
when matched then
update set prevprice = z.prevprice;
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
SharathData EngineerCommented:
You can try like this.
;with cte as (
  select *,row_number() over (partition by ModelID,Code order by BusDate) rn
    from test)
update c1
   set c1.PrevPrice = coalesce(c2.Price,0)
  from cte c1
  left join cte c2 on c1.rn = c2.rn + 1

Open in new window


check this. http://sqlfiddle.com/#!3/785590/13
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Query Syntax

From novice to tech pro — start learning today.