–一个题目涉及到的50个Sql语句
–(下面表的结构以给出,自己在数据库中建立表.并且添加相应的数据,数据要全面些. 其中Student表中,SId为学生的ID)
————————————表结构————————————–
–学生表tblStudent(编号StuId、姓名StuName、年龄StuAge、性别StuSex)
–课程表tblCourse(课程编号CourseId、课程名称CourseName、教师编号TeaId)
–成绩表tblScore(学生编号StuId、课程编号CourseId、成绩Score)
–教师表tblTeacher(教师编号TeaId、姓名TeaName)
———————————————————————————
–问题:
–1、查询“001”课程比“002”课程成绩高的所有学生的学号;
Select StuId From tblStudent s1
Where (Select Score From tblScore t1 Where t1.StuId=s1.stuId And t1.CourseId=’001′)>
(Select Score From tblScore t2 Where t2.StuId=s1.stuId And t2.CourseId=’002′)
–2、查询平均成绩大于60分的同学的学号和平均成绩;
Select StuId,Avg(Score) as AvgScore From tblScore
Group By StuId
Having Avg(Score)>60
–3、查询所有同学的学号、姓名、选课数、总成绩;
Select StuId,StuName,
SelCourses=(Select Count(CourseId) From tblScore t1 Where t1.StuId=s1.StuId),
SumScore=(Select Sum(Score) From tblScore t2 Where t2.StuId=s1.StuId)
From tblStudent s1
–4、查询姓“李”的老师的个数;
Select Count(*) From tblTeacher Where TeaName like ‘李%’
–5、查询没学过“叶平”老师课的同学的学号、姓名;
Select StuId,StuName From tblStudent
Where StuId Not In
(
Select StuID From tblScore sc
Inner Join tblCourse cu ON sc.CourseId=cu.CourseId
Inner Join tblTeacher tc ON cu.TeaId=tc.TeaId
Where tc.TeaName=’叶平’
)
–6、查询学过“001”并且也学过编号“002”课程的同学的学号、姓名;
Select StuId,StuName From tblStudent st
Where (Select Count(*) From tblScore s1 Where s1.StuId=st.StuId And s1.CourseId=’001′)>0
And
(Select Count(*) From tblScore s2 Where s2.StuId=st.StuId And s2.CourseId=’002′)>0
–7、查询学过“叶平”老师所教的所有课的同学的学号、姓名;
Select StuId,StuName From tblStudent st Where not exists
(
Select CourseID From tblCourse cu Inner Join tblTeacher tc On cu.TeaID=tc.TeaID
Where tc.TeaName=’叶平’ And CourseID not in
(Select CourseID From tblScore Where StuID=st.StuID)
)
–8、查询课程编号“002”的成绩比课程编号“001”课程低的所有同学的学号、姓名;
Select StuId,StuName From tblStudent s1
Where (Select Score From tblScore t1 Where t1.StuId=s1.stuId And t1.CourseId=’001′)>
(Select Score From tblScore t2 Where t2.StuId=s1.stuId And t2.CourseId=’002′)
–9、查询所有课程成绩小于60分的同学的学号、姓名;
Select StuId,StuName From tblStudent st
Where StuId Not IN
(Select StuId From tblScore sc Where st.StuId=sc.StuId And Score>60)
–10、查询没有学全所有课的同学的学号、姓名;
Select StuId,StuName From tblStudent st
Where (Select Count(*) From tblScore sc Where st.StuId=sc.StuId)<
(Select Count(*) From tblCourse)
–11、查询至少有一门课与学号为“1001”的同学所学相同的同学的学号和姓名;
——运用连接查询
Select DistInct st.StuId,StuName From tblStudent st
Inner Join tblScore sc ON st.StuId=sc.StuId
Where sc.CourseId IN (Select CourseId From tblScore Where StuId=’1001′)
——嵌套子查询
Select StuId,StuName From tblStudent
Where StuId In
(
Select Distinct StuId From tblScore Where CourseId In (Select CourseId From tblScore Where StuId=’1001′)
)
–12、查询至少学过学号为“1001”同学所有课程的其他同学学号和姓名;
Select StuId,StuName From tblStudent
Where StuId In
(
Select Distinct StuId From tblScore Where CourseId Not In (Select CourseId From tblScore Where StuId=’1001′)
–13、把“SC”表中“叶平”老师教的课的成绩都更改为此课程的平均成绩; (从子查询中获取父查询中的表名,这样也行????)
–创建测试表
Select * Into Sc From tblScore
go
Update Sc Set Score=(Select Avg(Score) From tblScore s1 Where s1.CourseId=sc.CourseId)
Where CourseId IN
(Select CourseId From tblCourse cs INNER JOIN tblTeacher tc ON cs.TeaID=tc.TeaID WHERE TeaName =’叶平’)
–14、查询和“1002”号的同学学习的课程完全相同的其他同学学号和姓名;
Select StuID,StuName From tblStudent st
Where StuId <> ‘1002’
And
Not Exists(Select * From tblScore sc Where sc.StuId=st.StuId And CourseId Not In (Select CourseId From tblScore Where StuId=’1002′))
And
Not Exists(Select * From tblScore Where StuId=’1002′ And CourseId Not In (Select CourseId From tblScore sc Where sc.StuId=st.StuId))
–15、删除学习“叶平”老师课的SC表记录;
Delete From tblScore Where CourseId IN
(Select CourseId From tblCourse cs INNER JOIN tblTeacher tc ON cs.TeaId=tc.TeaId Where tc.TeaName=’叶平’)
–16、向SC表中插入一些记录,这些记录要求符合以下条件:没有上过编号“003”课程的同学学号、’002’号课的平均成绩;
Insert Into tblScore (StuId,CourseId,Score)
Select StuId,’002′,(Select Avg(Score) From tblScore Where CourseId=’002′) From tblScore Where
StuId Not In (Select StuId From tblScore Where CourseId=’003′)
–17、按平均成绩从高到低显示所有学生的“数据库”、“企业管理”、“英语”三门的课程成绩,按如下形式显示: 学生ID,,数据库,企业管理,英语,有效课程数,有效平均分
Select StuId
,数据库=(Select Score From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where CourseName=’数据库’ And sc.StuID=st.StuId)
,企业管理=(Select Score From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where CourseName=’企业管理’ And sc.StuID=st.StuId)
,英语=(Select Score From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where CourseName=’英语’ And sc.StuID=st.StuId)
,有效课程数=(Select Count(Score) From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where (CourseName=’数据库’ or CourseName=’企业管理’ or CourseName=’英语’) And sc.StuID=st.StuId)
,有效平均分=(Select Avg(Score) From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where (CourseName=’数据库’ or CourseName=’企业管理’ or CourseName=’英语’) And sc.StuID=st.StuId)
From tblStudent st
Order by 有效平均分 Desc
–18、查询各科成绩最高和最低的分:以如下形式显示:课程ID,最高分,最低分
Select CourseId as 课程ID, 最高分=(Select Max(Score) From tblScore sc Where sc.CourseId=cs.CourseId ),
最低分=(Select Min(Score) From tblScore sc Where sc.CourseId=cs.CourseId )
From tblCourse cs
–19、按各科平均成绩从低到高和及格率的百分数从高到低顺序 (百分数后如何格式化为两位小数??)
Select 课程ID,平均分,及格率 From
(Select CourseId as 课程ID, 平均分=(Select Avg(Score) From tblScore sc Where sc.CourseId=cs.CourseId ),
及格率=Convert(varchar(10),((Select Count(*) From tblScore sc Where sc.CourseId=cs.CourseId And sc.Score>=60)*10000/(Select Count(*) From tblScore sc Where sc.CourseId=cs.CourseId))/100)+’%’
From tblScore cs) as tmp
Group by 课程ID,平均分,及格率
Order by 平均分, Convert(float,substring(及格率,1,len(及格率)-1)) Desc
–20、查询如下课程平均成绩和及格率的百分数(用”1行”显示): 企业管理(001),马克思(002),OO&UML (003),数据库(004)
Select 课程ID=sc.CourseId,课程名称=cs.CourseName,平均成绩=Avg(Score)
,及格率 =Convert(varchar(10),((Select Count(Score) From tblScore Where CourseId=sc.CourseId And Score>=60)*10000/Count(Score))/100.0)+’%’
From tblScore sc
Inner Join tblCourse cs ON sc.CourseId=cs.CourseId
Where sc.CourseId like ’00[1234]’
Group By sc.CourseId,cs.CourseName
–21、查询不同老师所教不同课程平均分从高到低显示
Select 课程ID=CourseId,课程名称=CourseName,授课教师=TeaName,平均成绩=(Select Avg(Score) From tblScore Where CourseId=cs.CourseId)
From tblCourse cs
Inner Join tblTeacher tc ON cs.TeaId=tc.TeaId
Order by 平均成绩 Desc
–22、查询如下课程成绩第 3 名到第 6 名的学生成绩单:企业管理(001),马克思(002),UML (003),数据库(004) 格式:[学生ID],[学生姓名],企业管理,马克思,UML,数据库,平均成绩
Select * From
(
Select Top 6 学生ID=StuId,学生姓名=StuName
,企业管理=(Select Score From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where CourseName=’企业管理’ And sc.StuID=st.StuId)
,马克思=(Select Score From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where CourseName=’马克思’ And sc.StuID=st.StuId)
,UML=(Select Score From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where CourseName=’UML’ And sc.StuID=st.StuId)
,数据库=(Select Score From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where CourseName=’数据库’ And sc.StuID=st.StuId)
,平均成绩=(Select Avg(Score) From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where (CourseName=’数据库’ or CourseName=’企业管理’ or CourseName=’UML’or CourseName=’马克思’) And sc.StuID=st.StuId)
,排名=Row_Number() Over(Order by(Select Avg(Score) From tblScore sc Inner Join tblCourse cs On sc.CourseId=cs.CourseId Where (CourseName=’数据库’ or CourseName=’企业管理’ or CourseName=’UML’or CourseName=’马克思’) And sc.StuID=st.StuId) DESC)
From tblStudent st
Order by 排名
) as tmp
Where 排名 between 3 And 6
–23、统计列印各科成绩,各分数段人数:课程ID,课程名称,[100-85],[85-70],[70-60],[ <60]
Select 课程ID=CourseId, 课程名称=CourseName
,[100-85]=(Select Count(*) From tblScore sc Where CourseId=cs.CourseId And Score between 85 And 100)
,[85-70]=(Select Count(*) From tblScore sc Where CourseId=cs.CourseId And Score between 70 And 84)
,[70-60]=(Select Count(*) From tblScore sc Where CourseId=cs.CourseId And Score between 60 And 69)
,[<60]=(Select Count(*) From tblScore sc Where CourseId=cs.CourseId And Score <60)
From tblCourse cs
–24、查询学生平均成绩及其名次
Select 学号=st.StuId, 姓名=StuName,平均成绩=sc.AvgScore,名次=(Dense_Rank() Over(Order by sc.AvgScore Desc)) From tblStudent st
Inner Join (Select StuId,Avg(Score) as AvgScore From tblScore Group by StuId) as sc On sc.StuId=st.StuId
Order by 学号
–25、查询各科成绩前三名的记录:(不考虑成绩并列情况)
Select 学号=StuId,课程号=CourseId,分数=Score
From
(Select Row_Number() Over(order by CourseId,Score Desc) as i,* From tblScore) as tmp –得到一个临时的排名表,其中i表示编号
Where i In
(
Select Top 3 i From (Select Row_Number() Over(order by CourseId,Score Desc) as i,* From tblScore) as t1 Where t1.CourseId=tmp.CourseId
)
–26、查询每门课程被选修的学生数
Select 课程ID=CourseId,选修人数=(Select Count(*) From (Select Distinct StuId From tblScore Where CourseId=cs.CourseId) as tmp)
From tblCourse cs
–27、查询出只选修了一门课程的全部学生的学号和姓名
Select 学号=StuId,姓名=StuName
From tblStudent st
Where (Select Count(*) From (Select Distinct CourseId From tblScore Where StuId=st.StuId) as tmp)=1
–28、查询男生、女生人数
Select 男生人数=(select Count(*) From tblStudent Where StuSex=’男’),
女生人数=(select Count(*) From tblStudent Where StuSex=’女’)
–29、查询姓“张”的学生名单
Select * From tblStudent Where StuName like ‘张%’
–30、查询同名同性学生名单,并统计同名人数
Select Distinct 学生姓名=StuName,同名人数=(Select Count(*) From tblStudent s2 Where s2.StuName=st.StuName) From tblStudent st
Where (Select Count(*) From tblStudent s2 Where s2.StuName=st.StuName)>=2
–31、1981年出生的学生名单(注:Student表中Sage列的类型是datetime)
Select * From tblStudent Where Year(Sage)=1981
–32、查询每门课程的平均成绩,结果按平均成绩升序排列,平均成绩相同时,按课程号降序排列
Select 课程ID=CourseId,课程名称=CourseName,平均成绩=(Select Avg(Score) From tblScore Where CourseId=cs.CourseId)
From tblCourse cs
Order by 平均成绩,CourseId Desc
–33、查询平均成绩大于85的所有学生的学号、姓名和平均成绩
Select 学号=StuId,姓名=StuName,平均成绩=(Select Avg(Score) From tblScore Where StuId=st.StuId) From tblStudent st
Where (Select Avg(Score) From tblScore Where StuId=st.StuId)>85
–34、查询课程名称为“数据库”,且分数低于60的学生姓名和分数
Select 姓名=StuName,分数=Score From tblScore sc
Inner Join tblStudent st On sc.StuId=st.StuId
Inner Join tblCourse cs On sc.CourseId=cs.CourseId
Where CourseName=’数据库’ And Score<60
–35、查询所有学生的选课情况;
Select 学号=StuId,选课数=(Select Count(*) From (Select Distinct CourseId From tblScore Where StuId=st.StuId) as tmp)
From tblStudent st
Select distinct 姓名=StuName,选修课程=CourseName From tblScore sc
Inner Join tblStudent st On sc.StuId=st.StuId
Inner Join tblCourse cs On sc.CourseId=cs.CourseId
–36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数;
Select 姓名=StuName,课程名称=CourseName,分数=Score From tblScore sc
Inner Join tblStudent st On sc.StuId=st.StuId
Inner Join tblCourse cs On sc.CourseId=cs.CourseId
Where Score>=70
–37、查询不及格的课程,并按课程号从大到小排列
Select * From tblScore Where Score<60 order by CourseId Desc
–38、查询课程编号为003且课程成绩在80分以上的学生的学号和姓名;
Select StuId,StuName From tblStudent
Where StuId in
(Select StuId From tblScore Where CourseId=’003′ And Score>=80)
–39、求选了课程的学生人数
Select 选了课程的学生人数=Count(*) From tblStudent st Where StuId IN (Select StuID From tblScore)
–40、查询选修“叶平”老师所授课程的学生中,成绩最高的学生姓名及其成绩
Select CourseId,CourseName
,该科最高学生=(Select StuName From tblStudent Where StuId in (Select Top 1 StuID From tblScore Where CourseId=cs.CourseId Order by Score Desc))
,成绩=(Select Top 1 Score From tblScore Where CourseId=cs.CourseId Order by Score Desc)
From tblCourse cs Inner Join tblTeacher tc ON cs.TeaId=tc.TeaId
Where TeaName=’叶平’
–41、查询各个课程及相应的选修人数
Select 课程ID=CourseId,选修人数=(Select Count(*) From (Select Distinct StuId From tblScore Where CourseId=cs.CourseId) as tmp)
From tblCourse cs
–42、查询不同课程成绩相同的学生的学号、课程号、学生成绩
Select 学号=StuId, 课程号=CourseId, 成绩=Score From tblScore sc
Where Exists (Select * From tblScore Where Score=sc.Score And StuId=sc.StuId And CourseId <>sc.CourseId)
Order by 学号,成绩
–43、查询每门功成绩最好的前两名
Select 课程号=CourseId,
第1名=(Select Top 1 StuId From tblScore Where CourseId=cs.CourseId Order by Score DESC),
第2名=(Select Top 1 StuID From (Select Top 2 StuId,Score From tblScore Where CourseId=cs.CourseId Order by Score DESC) as tmp Order by Score)
From tblCourse cs
–44、统计每门课程的学生选修人数(超过10人的课程才统计)。要求输出课程号和选修人数,查询结果按人数降序排列,若人数相同,按课程号升序排列
Select 课程ID=CourseId,选修人数=(Select Count(*) From (Select Distinct StuId From tblScore Where CourseId=cs.CourseId) as tmp)
From tblCourse cs
Where (Select Count(*) From (Select Distinct StuId From tblScore Where CourseId=cs.CourseId) as tmp)>=10
Order by 选修人数 DESC, 课程ID
–45、检索至少选修两门课程的学生学号
Select StuId from tblScore Group by Stuid having Count(*)>=2 –没有重复课程数据时可用此方法
–有重复课程时用此方法(如补考)
Select StuId from tblStudent st Where
(Select Count(*) From (Select Distinct CourseId From tblScore Where StuId=st.StuId) as tmp)>=2
–46、查询全部学生都选修的课程的课程号和课程名
Select CourseId,CourseName From tblCourse cs
Where Not Exists
(
Select * From tblStudent Where StuId Not In –没学过本课程的学生是否存在
(Select StuId From tblScore Where CourseId=cs.CourseId)
)
–47、查询没学过“叶平”老师讲授的任一门课程的学生姓名
Select StuId,StuName From tblStudent
Where StuId Not In
(
Select StuID From tblScore sc
Inner Join tblCourse cu ON sc.CourseId=cu.CourseId
Inner Join tblTeacher tc ON cu.TeaId=tc.TeaId
Where tc.TeaName=’叶平’
)
–48、查询两门以上不及格课程的同学的学号及其平均成绩
Select StuID as 学号,Avg(Score) as 平均成绩 From tblScore sc
Where (Select Count(*) From tblScore s1 Where s1.StuId=sc.StuId And Score<60)>=2
Group By StuId
–49、检索“004”课程分数小于60,按分数降序排列的同学学号 (ok)
Select StuID,Score From tblScore Where CourseId=’004′ And Score<60 Order by Score Desc
–50、删除“002”同学的“001”课程的成绩
Delete From SC Where StuId=’1002′ And CourseId=’001