Oracle SQL - 4지선다 문제 Decode 예제

select

qno, min(question), min(answer),

max(decode(opnum,1,optionstr,'')) op1,

max(decode(opnum,2,optionstr,'')) op2,

max(decode(opnum,3,optionstr,'')) op3,

max(decode(opnum,4,optionstr,'')) op4

from tbl_quiz, tbl_option

where qno = quizno(+)

group by qno;