如何在MS Access的单个查询中在一个字段中找到最小值，在另一个字段中找到关联值？

Question

I have a database of European countries. In the field on the very right, I have the population densities of all the listed countries. I have to find the smallest population density and display it and the country it belongs to in one query.

My best attempt:

SELECT Min(europa.Nepsuruseg) AS MinOfNepsuruseg, europa.Orszag
FROM europa
GROUP BY europa.Orszag;

This, however, displays all the countries and their population densities. How do I do this right?

Answer 1

You will first need to select the minimum population density across all records using a subquery.

Then in order to obtain all associated information held by the record or records whose population density field is equal to the minimum, you can either join the subquery to the main table, or include the subquery in the WHERE clause.

Here is an example using an INNER JOIN on the subquery:

select t.* 
from europa t inner join
(
    select min(e.nepsuruseg) as mpd from europa e
) q
on t.nepsuruseg = q.mpd

Or, using the WHERE clause:

select t.* 
from europa t
where t.nepsuruseg = (select min(e.nepsuruseg) from europa e)

Answer 2

You need to use the TOP function to grab just the smallest one, after you sort by Nepsuruseg.

SELECT Top 1 europa.Nepsuruseg, europa.Orszag
FROM europa
Order By europa.Nepsuruseg ASC;