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PostgreSQL Summary Stats and Window Functions

Here you can access the summer_medals table used in the course. To access the table, you will need to specify the medals schema in your queries (e.g., medals.summer_medals).

Note: When using sample integrations such as those that contain course data, you have read-only access. You can run queries, but cannot make any changes such as adding, deleting, or modifying the data (e.g., creating tables, views, etc.).

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Add notes about the concepts you've learned and SQL cells with queries you want to keep.

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DataFrameas
movie_info
variable
-- Add your own queries here
SELECT *
FROM medals.summer_medals
LIMIT 5

Explore Datasets

Use the summer_medals table to explore the data and practice your skills!

  • Select the athlete, event, and year from the summer_medals table.
    • Add another column, previous_winner, which contains the previous winner of the same event.
    • Filter your results for gold medalists.
  • Return the year, total number of medalists per year, and running total number of medalists in the history of the Summer Olympics.
    • Order your results by year in ascending order.
  • Return the country, year, and the number of gold medals earned.
    • Limit your results to the years 2004, 2008, and 2012.
    • Each country should have a subtotal of all gold medals earned across the three years.
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DataFrameas
df
variable
WITH Tennis_Gold AS (
  SELECT DISTINCT
    Gender, Year, Country
  FROM Summer_Medals
  WHERE
    Year >= 2000 AND
    Event = 'Javelin Throw' AND
    Medal = 'Gold')

SELECT
  Gender, Year,
  Country AS Champion,
  -- Fetch the previous year's champion by gender
  LAG(country) OVER (PARTITION BY gender
            ORDER BY gender ASC) AS Last_Champion
FROM Tennis_Gold
ORDER BY Gender ASC, Year ASC;
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DataFrameas
df1
variable
WITH Athlete_Medals AS (
  SELECT Athlete, COUNT(*) AS Medals
  FROM Summer_Medals
  GROUP BY Athlete
  HAVING COUNT(*) > 1),
  
  Thirds AS (
  SELECT
    Athlete,
    Medals,
    NTILE(3) OVER (ORDER BY Medals DESC) AS Third
  FROM Athlete_Medals)
  
SELECT
  -- Get the average medals earned in each third
  Third,
  AVG(Medals) AS Avg_Medals
FROM Thirds
GROUP BY Third
ORDER BY Third ASC;
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DataFrameas
df2
variable
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
  SUM(Medals) OVER
    (PARTITION BY country
     ORDER BY Year ASC
     ROWS BETWEEN
     2 PRECEDING AND CURRENT ROW) AS Medals_MA
FROM Country_Medals
ORDER BY Country ASC, Year ASC;