Moving total of countries' medals
What if your data is split into multiple groups spread over one or more columns in the table? Even with a defined frame, if you can't somehow separate the groups' data, one group's values will affect the average of another group's values.
Latihan ini adalah bagian dari kursus
PostgreSQL Summary Stats and Window Functions
Petunjuk latihan
- Calculate the 3-year moving sum of medals earned per country.
Latihan interaktif praktis
Cobalah latihan ini dengan menyelesaikan kode contoh berikut.
WITH Country_Medals AS (
SELECT
Year, Country, COUNT(*) AS Medals
FROM Summer_Medals
GROUP BY Year, Country)
SELECT
Year, Country, Medals,
-- Calculate each country's 3-game moving total
___ OVER
(PARTITION BY ___
ORDER BY Year ASC
ROWS BETWEEN
___ AND ___) AS Medals_MA
FROM Country_Medals
ORDER BY Country ASC, Year ASC;