Question

I’m trying to get the top 50 cities for all customer lists in our DB
(So simplified: every client has a list of customers with associated data(like the city))

If I say:

 SELECT top(50) clientid, city, COUNT(city) as cnt
 FROM customers
 GROUP BY clientid, city
 ORDER by cnt

it will limit the total resultset on 50 rows instead of limiting the results for every group.

How can I get the top 50 per clientid?

EDIT:
I searched stackoverflow (and googled) but only found solutions for Mysql. Probably searching for ‘limit’ will only find mysql solutions wince thats the keyword needed for that Database engine. If I know the keyword needed in Sql-Server I could find it as well using google.

Answer 1

;WITH cte
     As (SELECT clientid,
                city,
                COUNT(city) as cnt,
                ROW_NUMBER() OVER (PARTITION BY clientid 
                                       ORDER BY COUNT(city)) AS RN
         FROM   customers
         GROUP  BY clientid,
                   city)
SELECT clientid,
       city
FROM   cte
WHERE  RN <= 50