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 | 

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Answer 1

Here's how to do it without any temp tables:

Edit: simplified

select nf.country, nf.food_id as most_frequent_food_id
from national_foods nf
group by country, food_id 
having
  (country,count(*)) in (  
                        select country, max(cnt)
                        from
                          (
                          select country, food_id, count(*) as cnt
                          from national_foods nf1
                          group by country, food_id
                          )
                        group by country
                        having country = nf.country
                        )

Answer 2

select country,food_id, count(*) ne  
from   food f1  
group by country,food_id    
having count(*) = (select max(count(*))  
                   from   food f2  
                   where  country = f1.country  
                   group by food_id)  

Answer 3

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