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What about the weather

Regionally, Africa has a reputation for dominating in the field of running. However, Africa has the fewest athletes per (competing) country. Why?

Running events are only found in the Summer Olympics, so maybe Africa does not send many athletes to the Winter Games. This would explain the low number of athletes when looking across all Olympic Games.

Explore that hypothesis by looking at athlete counts by season (Summer versus Winter).

Este exercício faz parte do curso

Improving Query Performance in PostgreSQL

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Instruções do exercício

  • Add the season field from the athletes table to the SELECT statement.
  • Choose the join type to return only countries with competing athletes.
  • Sort by region and athletes_per_country to see if there is a difference between the summer and Winter Olympics.

Exercício interativo prático

Experimente este exercício completando este código de exemplo.

SELECT reg.region
  , ___
  , COUNT(DISTINCT ath.athlete_id) AS no_athletes
  , COUNT(DISTINCT reg.olympic_cc) AS no_countries
  , COUNT(DISTINCT ath.athlete_id)/COUNT(DISTINCT reg.olympic_cc) AS athletes_per_country
FROM athletes ath
___ JOIN oregions reg
  ON ath.country_code = reg.olympic_cc
GROUP BY reg.region, ___ -- Group by region and season
___ ___ , ___;
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