Question

So i have a table called cities with the attribute path (can have duplicate or more equal entries), name and kms, and i need to filter it so that i have entries with only one entry of each for path with the highest kms. what i have now is

SELECT cities.* 
FROM cities, categories 
group by cities.path , cities.kms 
ORDER BY cities.kms desc

the problem is that it gives me back duplicated entries for path( wich i dont want) and also it doesnt order it by kms like i want. What should i do?

Answer 1

I see no purpose for the categories table in your query, so I have eliminated it in my answer.

SELECT c1.path, c1.name, c1.kms
    FROM cities c1
        INNER JOIN (SELECT c2.path, MAX(c2.kms) AS Maxkms
                        FROM cities c2
                        GROUP BY c2.path) q
            ON c1.path = q.path
                AND c1.kms = q.Maxkms