returning only one row for each value of a column along with other values in different columns - sql

Question

I am working on a query on a SQL table which has several columns along with several rows of data and the query returns one row for each unique first and second columns based on the criteria given in the query.
For Example, I have the following table CC
product term bid offer bidcp offercp
AA sep14 20 10 x y
AA Sep14 15 9 p q
BA Sep14 30 15 as ps
XY Sep14 25 15 r t
XY Oct14 30 20 t r
XY Oct14 25 22 p q
When I run the query on the above table it should return the following data
product term bid offer bidcp offercp
AA sep14 20 9 x q(coming from a record which has lowest offer)
BA Sep14 30 15 as ps
XY Sep14 25 15 r t
XY Oct14 30 20 t r
When I executed the following query it grouped the data in CC even by bidcp and offercp and returned almost all the rows as both offercp and bidcp are unique in one or the other way but I just wanted bidcp and offercp to be where bid and offer are coming from assuming pair of both bid and offer are unique for each product and term
select product,term,max(bid) as bid,min(offer) as offer,bidcp,offercp from canadiancrudes where product like '%/%' group by product,term,bidcp,offercp
But, when I removed bidcp and offercp from groupby clause it threw me an obvious error
Column 'CC.BidCP' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.
Is there a better way to fix it?

Answer 1

In that case, you need 2 CTEs:
WITH o AS (
SELECT product,term,offer,offercp, ROW_NUMBER() OVER (PARTITION BY product, term ORDER BY offer ASC) AS rn
FROM canadiancrudes where product like '%/%'
)
, b AS (
SELECT product,term,bid,bidcp, ROW_NUMBER() OVER (PARTITION BY product, term ORDER BY bid DESC) AS rn
FROM canadiancrudes where product like '%/%'
)
SELECT o.product,o.term,b.bid,o.offer,b.bidcp,o.offercp
FROM o
INNER JOIN b
ON o.product=b.product
AND o.term=b.term
WHERE o.rn=1
AND b.rn=1

Answer 2

Use a CTE to get the min, max value -
WITH MaxMin_CTE AS (
SELECT product,term,max(bid) as bid,min(offer) AS Offer
FROM CC
GROUP BY product,term)
SELECT * from CC
INNER JOIN MaxMin_CTE ON CC.product = MaxMin_CTE .product
AND CC.bid= MaxMin_CTE.bid AND CC.Offer = MaxMin_CTE.offer
AND CC.Term = MaxMin_CTE.Term
Heres the SQL fiddle -
http://sqlfiddle.com/#!6/a6588/2