Filtering impacts
You will revisit filtering while examining the African countries with athletes competing in the Summer Olympics. You will look at the average age by gender for the Rio de Janeiro and Beijing games.
Along the way, you will compare the query plans using numeric filters, text filters, and indexed filters.
Questo esercizio fa parte del corso
Improving Query Performance in PostgreSQL
Esercizio pratico interattivo
Prova a risolvere questo esercizio completando il codice di esempio.
SELECT city, sex, COUNT(DISTINCT athlete_id), ___(___) AS avg_age
FROM athletes_summ
WHERE city IN ('Rio de Janeiro','Beijing')
GROUP BY city, sex;