Get most common value for each value of another column in SQL

Question

I have a table like this:

 Column  | Type | Modifiers 
---------+------+-----------
 country | text | 
 food_id | int  | 
 eaten   | date | 

<

Answer 1

SELECT DISTINCT
"F1"."food",
"F1"."country"
FROM "foo" "F1"
WHERE
"F1"."food" =
    (SELECT "food" FROM
        (
            SELECT "food", COUNT(*) AS "count"
            FROM "foo" "F2" 
            WHERE "F2"."country" = "F1"."country" 
            GROUP BY "F2"."food" 
            ORDER BY "count" DESC
        ) AS "F5"
        LIMIT 1
    )

Well, I wrote this in a hurry and didn't check it really well. The sub-select might be pretty slow, but this is shortest and most simple SQL statement that I could think of. I'll probably tell more when I'm less drunk.

PS: Oh well, "foo" is the name of my table, "food" contains the name of the food and "country" the name of the country. Sample output:

   food    |  country   
-----------+------------
 Bratwurst | Germany
 Fisch     | Frankreich