SELECT First(选课成绩.课程编号) AS [课程编号 字段], First(选课成绩.考试成绩) AS [考试成绩 字段], Count(选课成绩.课程编号) AS NumberOfDupsFROM 选课成绩GROUP BY 选课成绩.课程编号, 选课成绩.考试成绩HAVING (((Count(选课成绩.课程编号))>1) AND ((Count(选课成绩.考试成绩))>1));请将语句进行运行，并说出语句的功能：