Session Ready
Exercise

Set theory challenge

Congratulations! You've now made your way to the challenge problem for this third chapter. Your task here will be to incorporate two of UNION/UNION ALL/INTERSECT/EXCEPT to solve a challenge involving three tables.

In addition, you will use a subquery as you have in the last two exercises! This will be great practice as you hop into subqueries more in Chapter 4!

Instructions
100 XP
  • Identify the country codes that are included in either economies or currencies but not in populations.
  • Use that result to determine the names of cities in the countries that match the specification in the previous instruction.