QuatoHub

SELECT salary * months AS earnings, COUNT(*) FROM Employee
GROUP BY earnings ORDER BY earnings DESC LIMIT 1;

QuatoHub

SELECT CEIL(AVG(Salary) - AVG(REPLACE(Salary, 0, ""))) FROM EMPLOYEES;

QuatoHub

SELECT MAX(POPULATION) - MIN(POPULATION) FROM CITY;

QuatoHub

SELECT SUM(POPULATION) FROM CITY WHERE  COUNTRYCODE = "JPN";

QuatoHub

SELECT FLOOR(AVG(POPULATION)) FROM CITY;

QuatoHub

SELECT AVG(POPULATION) FROM CITY WHERE DISTRICT = "California";

QuatoHub

SELECT SUM(POPULATION) FROM CITY WHERE DISTRICT = "California";

QuatoHub

SELECT COUNT(*) FROM CITY WHERE POPULATION > 100000;

QuatoHub

SET @r1=0, @r2=0, @r3=0, @r4=0;
SELECT MIN(Doctor), MIN(Professor), MIN(Singer), MIN(Actor)
FROM(
  SELECT 
    CASE 
        WHEN Occupation="Doctor" THEN (@r1:=@r1+1)
        WHEN Occupation="Professor" THEN (@r2:=@r2+1)
        WHEN Occupation="Singer" THEN (@r3:=@r3+1)
        WHEN Occupation="Actor" THEN (@r4:=@r4+1) 
    END AS RowNumber,

QuatoHub

SELECT CONCAT(NAME, "(", LEFT(OCCUPATION, 1), ")") FROM OCCUPATIONS ORDER BY NAME;

SELECT CONCAT("There are a total of ", COUNT(OCCUPATION), " ", LOWER(OCCUPATION), "s.") 
FROM OCCUPATIONS GROUP BY OCCUPATION ORDER BY COUNT(OCCUPATION), OCCUPATION;