Group BY with multiple selects (Oracle) - sql

Question

Im having a problem using group by with multiple selects. I want to select the minimum bid offer price for each Auction. But I also have to get the name of the user who made that Bid. As you can see in the results, I get multiple results for each auction, and if I remove elements from the Groupby statement I get an error message. How can I groupy by ID_Auction and still show the name of the User? Thanks for the help
SELECT A.ID_AUCTION,MIN(B.PRICE) AS PRICE,U.NAME
FROM AUCTION A,BIDS B,USERS U,PRODUCT P
WHERE P.TYPE='CocaCola'
--Joins
and A.ID_AUCTION=B.ID_AUCTION
and BID.ID_USER=U.ID_USER
and A.ID_PRODUCT=P.ID_PRODUCT
GROUP BY A.ID_AUCTION,U.NAME;
ID_AUCTION PRICE NAME
---------- ---------- -------------- ------------------------------------------
27 25 Andrew
28 40 John
27 30 Michael
28 35 Peter
The Output I Desire :
ID_AUCTION PRICE NAME
---------- ---------- -------------- ------------------------------------------
27 25 Andrew
28 35 Peter

Answer 1

SELECT A.ID_AUCTION,MIN(B.PRICE) AS PRICE,U.NAME
FROM AUCTION A,BIDS B,USERS U,PRODUCT P
WHERE P.TYPE='CocaCola'
--Joins
and A.ID_AUCTION=B.ID_AUCTION
and BID.ID_USER=U.ID_USER
and A.ID_PRODUCT=P.ID_PRODUCT
GROUP BY A.ID_AUCTION,U.NAME;
Should probably be like:
SELECT A.ID_AUCTION, U.NAME, B.PRICE as PRICE
from AUCTION A
inner join (SELECT ID_AUCTION, NAME, MIN(Price) from Bids order by 1,2,3) B
ON a.ID_AUCTION = b.ID_AUCTION
inner join Users U
ON B.ID_USER = U.ID_USER
inner join Product P
ON A.ID_PRODUCT = P.ID_PRODUCT
WHERE P.TYPE = 'CocaCola'
GROUP BY A.ID_AUCTION, U.NAME
I've never seen joins work the way you did it, but that might be an Oracle thing...actually I think that's considered bad practice in most SQL arenas...

Answer 2

Give this a try, this will do the trick. It is ok with the coding style. Some old systems still work well with the ANSI-89 SQL style:
SELECT A.ID_AUCTION,
B.PRICE,
U.NAME
FROM AUCTION A,
BIDS B,
USERS U,
PRODUCT P
WHERE P.TYPE='CocaCola' --Joins
AND A.ID_AUCTION=B.ID_AUCTION
AND B.ID_USER=U.ID_USER
AND A.ID_PRODUCT=P.ID_PRODUCT
AND B.PRICE = (SELECT MIN(bids.PRICE) FROM BIDS --get only the bid with MIN price
WHERE bids.ID_AUCTION = A.ID_AUCTION);

Answer 3

select * from
(
SELECT A.ID_AUCTION,B.PRICE,U.NAME,
Dense_Rank() over (partition by ID_AUCTION order by Price Asc)AS Rank
FROM
AUCTION A
JOIN
BIDS B
ON A.ID_AUCTION=B.ID_AUCTION
JOIN
USERS U
ON BID.ID_USER=U.ID_USER
JOIN
PRODUCT P
ON A.ID_PRODUCT=P.ID_PRODUCT
WHERE P.TYPE='CocaCola')
where rank='1'

Answer 4

First should just group by A.ID_AUCTION and second on your select you could try a min(U.NAME)
SELECT A.ID_AUCTION,MIN(B.PRICE) AS PRICE,min(U.NAME)
FROM AUCTION A,BIDS B,USERS U,PRODUCT P
WHERE P.TYPE='CocaCola'
--Joins
and A.ID_AUCTION=B.ID_AUCTION
and BID.ID_USER=U.ID_USER
and A.ID_PRODUCT=P.ID_PRODUCT
GROUP BY A.ID_AUCTION;