Exercise

Comparing two set operations

You learned in the video exercise that UNION ALL returns duplicates, whereas UNION does not. In this exercise, you will dive deeper into this, looking at cases for when UNION is appropriate compared to UNION ALL.

You will be looking at combinations of country code and year from the economies and populations tables.

Instructions 1/2

undefined XP
  • 1
    • Perform an appropriate set operation that determines all pairs of country code and year (in that order) from economies and populations, excluding duplicates.
    • Order by country code and year.
  • 2
    • Amend the query to return all combinations (including duplicates) of country code and year in the economies or the populations tables.