Familiar question, but with Vertica. I'd like to return the top 5 geo_country rows based on sum(imps) for each tag_id. This is the query I started:
SELECT tag_id,
geo_country,
SUM(imps) AS imps,
RANK() OVER (PARTITION BY tag_id ORDER BY SUM(imps) DESC) AS rank
FROM table1
WHERE tag_id IN (2013150,1981153)
AND ymd > CURRENT_DATE - 3
GROUP BY 1,
2 LIMIT 10;
This actually returns only rows from the first tag in the WHERE clause (2013150). I know that the other tag has sum(imps) values high enough which should include it in the results.
Also, how do I implement the Top N part? I tried adding a LIMIT clause within the OVER function, but it doesn't look like it is an accepted parameter.
Solved. The solution is to convert the query to a subquery and then use the WHERE clause to filter by rank: