/*native country and saklary level*/
SELECT nativecountry,
    SUM (CASE WHEN salarylevel = '>50K' THEN 1 ELSE 0 END) high_salary,
    SUM (CASE WHEN salarylevel = '<=50K' THEN 1 ELSE 0 END) low_salary
FROM person
GROUP BY  nativecountry 
ORDER BY 2 DESC;