Question

I have this table:

id | owner | asset | rate
-------------------------
1  | 1     | 3     | 1
2  | 1     | 4     | 2
3  | 2     | 3     | 3
4  | 2     | 5     | 4

And i’m using

SELECT asset, max(rate)
FROM test 
WHERE owner IN (1, 2)
GROUP BY asset
HAVING count(asset) > 1
ORDER BY max(rate) DESC

to get intersection of assets for specified owners with best rate.

I also need id of row used for max(rate), but i can’t find a way to include it to SELECT. Any ideas?

Edit:

I need

• Find all assets that belongs to both owners (1 and 2)
• From the same asset i need only one with the best rate (3)
• I also need other columns (owner) that belongs to the specific asset with best rate

I expect the following output:

id | asset | rate
-------------------------
3  | 3     | 3

Oops, all 3s, but basically i need id of 3rd row to query the same table again, so resulting output (after second query) will be:

id | owner | asset | rate
-------------------------
3  | 2     | 3     | 3

Let’s say it’s Postgres, but i’d prefer reasonably cross-DBMS solution.

Edit 2:

Guys, i know how to do this with JOINs. Sorry for misleading question, but i need to know how to get extra from existing query. I already have needed assets and rates selected, i just need one extra field among with max(rate) and given conditions if it’s possible.

Answer 1

Another solution that might or might not be faster than a self join (depending on the DBMS’ optimizer)

SELECT id, 
       asset,
       rate,
       asset_count
FROM (
    SELECT id,
           asset, 
           rate,
           rank() over (partition by asset order by rate desc) as rank_rate,
           count(asset) over (partition by null) as asset_count
    FROM test 
    WHERE owner IN (1, 2)
) t
WHERE rank_rate = 1
ORDER BY rate DESC