Moving maximum of Scandinavian athletes' medals
Frames allow you to restrict the rows passed as input to your window function to a sliding window for you to define the start and finish.
Adding a frame to your window function allows you to calculate "moving" metrics, inputs of which slide from row to row.
Deze oefening maakt deel uit van de cursus
PostgreSQL Summary Stats and Window Functions
Oefeninstructies
- Return the year, medals earned, and the maximum medals earned, comparing only the current year and the next year.
Praktische interactieve oefening
Probeer deze oefening eens door deze voorbeeldcode in te vullen.
WITH Scandinavian_Medals AS (
SELECT
Year, COUNT(*) AS Medals
FROM Summer_Medals
WHERE
Country IN ('DEN', 'NOR', 'FIN', 'SWE', 'ISL')
AND Medal = 'Gold'
GROUP BY Year)
SELECT
-- Select each year's medals
___,
___,
-- Get the max of the current and next years' medals
___ OVER (ORDER BY ___ ASC
ROWS BETWEEN ___
AND ___) AS Max_Medals
FROM Scandinavian_Medals
ORDER BY Year ASC;