Databases · Junior · Question 27 of 75

What does this query return?

SELECT city, COUNT(*)
FROM users
GROUP BY city;

1Every user with their city
✓Correct answer: One row per city with the number of users in it
3The total number of users

Explanation

GROUP BY collapses rows with the same value into one, and aggregate functions are computed for each group.

Further reading

PostgreSQL: Aggregate functions ↗

Test yourself

Take the Databases · Junior quiz: questions and options are shuffled, and you get a review of your mistakes at the end.