NOT IN with IS NOT NULL
You want to know which country capitals have never been the closest city to recorded earthquakes. You decide to use NOT IN to compare Capital from the Nations table, in the outer query, with NearestPop, from the Earthquakes table, in a sub-query.
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SELECT WorldBankRegion,
CountryName,
___ -- Capital city name column
FROM Nations
WHERE Capital NOT IN
(SELECT ___ -- City name column
FROM Earthquakes);