A.CREATE VIEW LH AS; SELECT KC.课程号,KC.课程名,SKB.学号,SKB.成绩; FROM KC,SKB; WHERE 成绩>=80 B.CREATE VIEW LH AS: SELECT KC.课程号,KC.课程名,SKB.学号,SKB.成绩; FROM KC INNER JOIN SKB; ON 成绩>=80 C.CREATE VIEW LH AS; SELECT KC.课程号,KC.课程名,SKB.学号,SKB.成绩; FROM KC INNER JOIN SKB; ON KC.课程号=JKB.课程号; WHERE 成绩>=80 D.CREATE VIEW LH AS; SELECT KC.课程号,KC.课程名,SKB.学号,SKB.成绩; FROM KC INNER JOIN SKB; ON KC.课程号=JKB.课程号; GROUP BY 课程号; HAVING 成绩>=80