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.

Take Hint (-30 XP)