Question

I have some kind of problem to understand something.

I have the next table:

ID  PROD    PRICE
1   A        10
2   B        20
3   C        30
4   A        1
5   B        12
6   C        2
7   A        7
8   B        8
9   C        9
10  A        5
11  B        2

I want to get all the minimum prices of all the prod, meaning I want to get 3 records, the minimum price for every prod.
From the example above, this is what I want to get:

ID  PROD    MIN(PRICE)
4   A       1
11  B       2
6   C       2

This is the query I wrote:

select id, prod, min(price)
from A1
group by(prod);

But this is the records I got:

ID  PROD    MIN(PRICE)
1   A        1
2   B        2
3   C        2

As you can see the ID value is wrong, it is only give me some kind of line counter and not the actual ID value.

You can check it at the next link

What I’m doing wrong?

Answer 1

SELECT  a.*
FROM    A1 a
        INNER JOIN
        (
            SELECT Prod, MIN(Price) minPrice
            FROM A1
            GROUP BY Prod
        ) b ON a.Prod = b.Prod AND
                a.Price = b.minPrice

• SQLFiddle Demo

For MSSQL

SELECT ID, Prod, Price
FROM
(
  SELECT ID, Prod, Price,
        ROW_NUMBER() OVER(Partition BY Prod ORDER BY Price ASC) s
  FROM A1
) a
WHERE s = 1

• SQLFiddle Demo