Why SQL HAVING SUM(column) comparison with number does not work?

Try to find the continents where all countries have a population <= 25000000 from the world table below as in Difficult Questions That Utilize Techniques Not Covered In Prior Sections.

The SQL below returns nothing but not sure why. Please advise.

SELECT 
    continent, 
    SUM(population) as total
FROM 
    world
GROUP BY 
    continent
HAVING SUM(population) <= 25000000

Without HAVING, it returns rows as below:

SELECT 
    continent, 
    SUM(population) as total
FROM 
    world
GROUP BY 
    continent
/* HAVING SUM(population) <= 25000000 */

Because none of the populations added up for the continents is less than 25,000,000. The smallest is Caribbean at 36,149,204

Did you mean to have HAVING SUM(population) <= 250000000 (one more zero)

Then you would get three rows returned.

However the question asks you to return "Find the continents where all countries have a population <= 25000000. Then find the names of the countries associated with these continents. Show name, continent and population.". So your query doesn't do this.

The correct answer can be found by looking for a continent where any of the countries populations (not the total of them) exceed the number and excluding those continents using a NOT IN

SELECT name, continent, population
FROM world
WHERE Continent NOT IN
(
SELECT DISTINCT Continent
FROM world
WHERE population > 25000000
)

There probably is also a way to do it using the ALL clause, which is probably what they wanted.