MySchool 04 高级查询 上机题

 --上机题1
 --参加oop最近一次考试时间的最高分数和最低分数
 select MAX(studentresult), MIN(studentresult) from Result
 where ExamDate=
 (
 select MAX(ExamDate) from Result
 where SubjectId=
 (
 select SubjectId from Subject where SubjectName='oop'
 )
 )
 and SubjectId=
 (
 select SubjectId from Subject where SubjectName='oop'
 )
 --上机题2
 --使用in关键字的子查询来查询S1学期开设的课程
 select SubjectName from Subject
 where GradeId in
 (
     select GradeId from Grade where GradeName='S1'
 )
 --上机题3
 --查询某课程最近一次考试缺考的学生名单
 select studentno, StudentName from Student
 where StudentNo not in
 (
   select StudentNo from Result
   where SubjectId=
   (
   select SubjectId from Subject where SubjectName='oop'
   )
   and ExamDate=
 (
 select MAX(ExamDate) from Result
 where SubjectId=
 (
 select SubjectId from Subject where SubjectName='oop'
 )
 )
 )
  and GradeId=
 (
 select GradeId from Subject where SubjectName='oop'
 )
 --上机题4
 --检查并更新S1的学生为S2
 if exists(
 select studentno,StudentName from Student
 where StudentNo in
 (
   select StudentNo from Student where
   GradeId=
   (
   sleelct GradeId from grade where GradeName='S1'
   )
 )
 )
 begin
 update Student set GradeId=2
 where GradeId in
 (
   select GradeId from Grade where GradeName='S1'
 )
 end
 --上机题5
 select studentname,(select GradeName from Grade)as Gradename,subjectname,examdate,studentresult from  Student,Subject,Result
 where result.StudentNo in
 (
    select MAX(ExamDate) from Result
    group by SubjectId
 )
 --上机题6
 --SQL语句的综合运用
 --赋值科目名称为oop
 declare @subjectName varchar(50)
 SET @subjectName='oop'
 --科目为oop最近考试时间
 declare @date datetime
 select @date=MAX(examdate) from Result
 inner join Subject on Result.SubjectId=Subject.SubjectId
 where SubjectName=@subjectName
 --课程oop的编号
 declare @subjectNo int
 select @subjectNo=SubjectId from Subject where SubjectName=@subjectName
 --统计考试缺考情况
 SELECT 应到人数=(
                  SELECT COUNT(*)  FROM Student
                  INNER JOIN Subject ON Subject.GradeId=Student.GradeId
                  WHERE SubjectName= @subjectName
                  ) ,
       实到人数=(
                 SELECT COUNT(*) FROM Result
                 WHERE ExamDate=@date AND SubjectNo=@subjectNo
                ),
       缺考人数=(
                  SELECT COUNT(*)  FROM Student
                  INNER JOIN Subject ON Subject.GradeId=Student.GradeId
                  WHERE SubjectName= @subjectName
               ) -
               (
                  SELECT COUNT(*) FROM Result
                  WHERE ExamDate=@date AND SubjectNo=@subjectNo
               )
 --统计考试通过情况，并将统计结果存放在新表TempResult中--
 IF EXISTS(SELECT * FROM sysobjects WHERE name='TempResult')
   DROP TABLE TempResult
 SELECT  Student.StudentName,Student.StudentNo,StudentResult,
         IsPass=CASE
                  WHEN StudentResult>=60  THEN 1
                  ELSE 0
                END
  INTO TempResult
 FROM Student LEFT JOIN (
                          SELECT * FROM Result  WHERE ExamDate=@date AND SubjectNo=@subjectNo
                         ) R
 ON Student.StudentNo=R.StudentNo
 WHERE GradeId=(SELECT GradeId FROM Subject WHERE SubjectName= @subjectName)
 SELECT * FROM TempResult
 DECLARE @avg numeric(4,1)
 SELECT @avg=AVG(StudentResult) FROM TempResult WHERE StudentResult IS NOT NULL
 --判断平均分是否低于60分。如果低于60分，设置平均分为60分
 IF (@avg<60)
  SET @avg=60
 --循环加分，最高分不能超过97分
 WHILE (1=1)
 BEGIN
    IF(NOT Exists(SELECT * FROM TempResult WHERE StudentResult<@avg))
       BREAK
    ELSE
      UPDATE TempResult SET StudentResult=StudentResult+1
      WHERE StudentResult<@avg AND StudentResult<97
 END
  --因为提分，所以需要更新IsPass（是否通过）列的数据
 UPDATE TempResult
   SET IsPass=CASE
                WHEN StudentResult>=60  THEN 1
                ELSE  0
             END
 SELECT * FROM newTable
 --显示考试最终通过情况
 SELECT 姓名=StudentName,学号=StudentNo,
        成绩=CASE
               WHEN StudentResult IS NULL THEN '缺考'
               ELSE  CONVERT(varchar(5),StudentResult)
             END,
    是否通过=CASE
               WHEN isPass=1 THEN '是'
               ELSE  '否'
            END
  FROM TempResult
 --显示通过率及通过人数
 SELECT 总人数=COUNT(*) ,通过人数=SUM(IsPass),
        通过率=(CONVERT(varchar(5),AVG(IsPass*100))+'%')  FROM TempResult
 GO
 [sql] view plain copy 在CODE上查看代码片派生到我的代码片
 //经典案例
 --参加oop最近一次考试时间的最高分数和最低分数
 select MAX(studentresult), MIN(studentresult) from Result
 where ExamDate=
 (
 select MAX(ExamDate) from Result
 where SubjectId=
 (
 select SubjectId from Subject where SubjectName='oop'
 )
 )
 and SubjectId=
 (
 select SubjectId from Subject where SubjectName='oop'
 )
 ----参加oop最近一次考试时间的学生姓名和学生编号
 select studentno, studentname from Student
 where StudentNo in
 (
   select StudentNo from result
   where subjectid=
   (
    select subjectid from Subject where SubjectName='oop'
   )
   and ExamDate=
   (
   select MAX(ExamDate) from Result
   where subjectid=
   (
    select subjectid from Subject where SubjectName='oop'
   )
   )
 )
 --案例：检查“oop”课程最近一次考试。--如果有分以上的成绩，则每人提分；
 --否则，每人提分。最终的成绩不得大于分
 if exists(
  select studentresult from Result
    where subjectid=
   (
    select subjectid from Subject where SubjectName='oop'
   )
   and ExamDate=
   (
   select MAX(ExamDate) from Result
   where subjectid=
   (
    select subjectid from Subject where SubjectName='oop'
   )
   )
  and StudentResult>80
 )
 begin
 update Result set StudentResult=100
   where subjectid=
   (
    select subjectid from Subject where SubjectName='oop'
   )
   and ExamDate=
   (
   select MAX(ExamDate) from Result
   where subjectid=
   (
    select subjectid from Subject where SubjectName='oop'
   )
   )
 and StudentResult>98
 update Result set StudentResult+=2
   where subjectid=
   (
    select subjectid from Subject where SubjectName='oop'
   )
   and ExamDate=
   (
   select MAX(ExamDate) from Result
   where subjectid=
   (
    select subjectid from Subject where SubjectName='oop'
   )
   )
 and StudentResult<=98
 end
 else
 begin
 update Result set StudentResult+=5
   where subjectid=
   (
    select subjectid from Subject where SubjectName='oop'
   )
   and ExamDate=
   (
   select MAX(ExamDate) from Result
   where subjectid=
   (
    select subjectid from Subject where SubjectName='oop'
   )
   )

 end