select ssno, objectivechoice, count(1) cnt from tbl_answer where ssno = 147 group by ssno, objectivechoice order by cnt desc

select ssno, objectivechoice, count(1) cnt from tbl_answer where ssno = 147 and objectivechoice is not null group by ssno, objectivechoice order by cnt desc

cnt1~4 만으로도 충분히 의미 전달 됩니다.
objectivechoice1~4 는 굳이 필요 없어 보입니다.
 

SELECT ssno
--     , MIN(CASE objectivechoice WHEN 1 THEN objectivechoice END) objectivechoice1
     , COUNT(CASE objectivechoice WHEN 1 THEN 1 END) cnt1
--     , MIN(CASE objectivechoice WHEN 2 THEN objectivechoice END) objectivechoice2
     , COUNT(CASE objectivechoice WHEN 2 THEN 1 END) cnt2
--     , MIN(CASE objectivechoice WHEN 3 THEN objectivechoice END) objectivechoice3
     , COUNT(CASE objectivechoice WHEN 3 THEN 1 END) cnt3
--     , MIN(CASE objectivechoice WHEN 4 THEN objectivechoice END) objectivechoice4
     , COUNT(CASE objectivechoice WHEN 4 THEN 1 END) cnt4
  FROM tbl_answer
 WHERE ssno = 147
   AND objectivechoice IS NOT NULL
 GROUP BY ssno
;

GROUP BY ssno