每日练习20171031

方法一：
SELECT s1.name
FROM student_score s1,student_score s2,student_score s3
WHERE s1.course=’语文’ AND s1.score>80
AND s2.course=’数学’ AND s2.score>80
AND s3.course=’英语’ AND s3.score>80
AND s1.name=s2.name AND s1.name=s3.name
方法二：
SELECT DISTINCT name FROM student_score WHERE name NOT IN
(SELECT name FROM student_score WHERE score <= 80 )