Reigning champions by gender and event
In the previous exercise, you partitioned by gender to ensure that data about one gender doesn't get mixed into data about the other gender. If you have multiple columns, however, partitioning by only one of them will still mix the results of the other columns.
Questo esercizio fa parte del corso
PostgreSQL Summary Stats and Window Functions
Istruzioni dell'esercizio
- Return the previous champions of each year's events by gender and event.
Esercizio pratico interattivo
Prova a risolvere questo esercizio completando il codice di esempio.
WITH Athletics_Gold AS (
SELECT DISTINCT
Gender, Year, Event, Country
FROM Summer_Medals
WHERE
Year >= 2000 AND
Discipline = 'Athletics' AND
Event IN ('100M', '10000M') AND
Medal = 'Gold')
SELECT
Gender, Year, Event,
Country AS Champion,
-- Fetch the previous year's champion by gender and event
___ OVER (___
ORDER BY Year ASC) AS Last_Champion
FROM Athletics_Gold
ORDER BY Event ASC, Gender ASC, Year ASC;