3.occupations.sql

SELECT MIN(CASE WHEN OCCUPATION = 'DOCTOR' THEN NAME ELSE NULL END),
       MIN(CASE WHEN OCCUPATION = 'PROFESSOR' THEN NAME ELSE NULL END),
       MIN(CASE WHEN OCCUPATION = 'SINGER' THEN NAME ELSE NULL END),
       MIN(CASE WHEN OCCUPATION = 'ACTOR' THEN NAME ELSE NULL END)
  FROM (SELECT OCCUPATION, 
               NAME, 
               ROW_NUMBER() OVER (PARTITION BY OCCUPATION ORDER BY NAME) AS RN
          FROM OCCUPATIONS) AS T
 GROUP BY RN;