例:给出所有选修3-105课程学生的分数，并做划分，90分以上A档，80-89分B档，70-79分C档，60-69分D档，59分以下E档.

SELECT SNO,DEGREE,

CASE 

WHEN DEGREE>=90 THEN 'A'

WHEN DEGREE BETWEEN 80 AND 89 THEN 'B'

WHEN DEGREE BETWEEN 70 AND 79 THEN 'C'

WHEN DEGREE BETWEEN 60 AND 69 THEN 'D'

WHEN DEGREE <=59 THEN 'E'

END AS CLASS

FROM SCORE WHERE CNO='3-105'

ORDER BY CLASS