select sum(ct.POPULATION) from CITY ct, COUNTRY cntry
where ct.COUNTRYCODE = cntry.CODE
and cntry.CONTINENT = 'Asia';
African Cities
select ct.NAME from CITY ct, COUNTRY cntry
where ct.COUNTRYCODE = cntry.CODE
and cntry.CONTINENT = 'Africa';
Average Population of Each Continent
select COUNTRY.CONTINENT, floor(avg(CITY.POPULATION))
from CITY, COUNTRY
where CITY.COUNTRYCODE = COUNTRY.CODE
group by COUNTRY.CONTINENT;
The Report
SELECT
CASE WHEN Grades.Grade<8 THEN NULL ELSE Students.Name END,
Grades.Grade,
Students.Marks
FROM Students JOIN Grades
ON Students.Marks BETWEEN Grades.Min_Mark AND Grades.Max_Mark
ORDER BY Grades.Grade DESC, Students.Name, Students.Marks
