Question

I have issues in query:

 priceDeatil 
 ProductCode  BusinessUnit  price   DateFrom     DateTo
  10001         ORB          12.00   12-08-2011   31-09-2015
  10001         ORB          21.00   01.08-2011   15-11-2011
  10002         ORB          31.00   01.04-2011   15-08-2012
  10003         ORB          42.00   01.05-2011   15-08-2012

My query is:

 SELECT     BusinessUnit, ProductCode,  DateFrom, DateTo, Price
 FROM         WMPriceDetail
 WHERE     (DateFrom < 'Sep 01 2011') AND (DateTo > 'Sep 01 2011' OR DateTo = '')
 ORDER BY ProductCode

This return

   priceDeatil 
 ProductCode  BusinessUnit  price   DateFrom     DateTo
  10001         ORB          12.00   12-08-2011   31-09-2015
  10001         ORB          21.00   01.08-2011   15-11-2011
  10002         ORB          31.00   01.04-2011   15-08-2012
  10003         ORB          42.00   01.05-2011   15-08-2012

But Here productCode 10001 return two records; That time I want to get the Max Date i.e 12-08-2011 .

So desired result should be like this:

   priceDeatil 
 ProductCode  BusinessUnit  price   DateFrom     DateTo
  10001         ORB          12.00   12-08-2011   31-09-2015
  10002         ORB          31.00   01.04-2011   15-08-2012
  10003         ORB          42.00   01.05-2011   15-08-2012

How to write query for this situation?

Answer 1

 SELECT     BusinessUnit, ProductCode,  DateFrom, DateTo, Price FROM
 (SELECT    BusinessUnit, ProductCode,  DateFrom, DateTo, Price, 
 rank() over (PARTITION BY ProductCode ORDER BY DateFrom DESC) rank_num
 FROM  WMPriceDetail
 WHERE (DateFrom < 'Sep 01 2011') AND (DateTo > 'Sep 01 2011' OR DateTo = '') t 
 WHERE rank_num=1
 ORDER BY ProductCode