SQL高级查询

t_tudent(sid,sname,sage,ssex,sdept) 学生表


t_course(cid,cname,tid) 课程表


t_score( scid,sid,cid,grade) 成绩表


t_teacher(tid,tname) 教师表


问题：


1、查询“001”课程比“002”课程成绩高的所有学生的学号;


select t1.sid from


(select sid,grade from t_score where cid = '001') t1,


(select sid,grade from t_score where cid = '002') t2


where t1.grade >t2.grade and t1.sid = t2.sid;


select t2.sid,t2.ca,t2.cb(


select t1.sid,sum(t1.ca) ca,sum(t1.cb) cb


from


(


select sid,


CASE WHEN cid = '001' THEN grade ELSE 0 END ca,


CASE WHEN cid = '002' THEN grade ELSE 0 END cb


from t_score


)t1


GROUP BY sid


)t2


where t2.ca > t2.cb


2、查询平均成绩大于60分的同学的学号和平均成绩;


select sid,avg(grade ) from t_score


group by sid


having avg(grade ) >60;


3、查询所有同学的学号、姓名、选课数、总成绩;


select t1.sid,t1.sname,count(t2.cid),sum(grade ) from t_student t1


left join t_score t2


on t1.sid = t2sid


group by t1sid,t1.sname;


4、查询姓“李”的老师的个数;


select count(distinct(tname)) from t_teacher where tname like '李%';


5、查询没学过“叶平”老师课的同学的学号、姓名;


select sid, sname from t_student


where sid not in


(


select distinct(t1.sid) from t_score t1,t_course t2,t_teacher t3


where t1.cid = t2.cid and t3.tid = t2.tid and t3.tname = '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 t0.sid,t0.sname from t_student t0, t_score t1


where t0.sid = t1.sid and t1.cid = '001'


and exists


(


select * from t_score t2 where t2.sid = t1.sid and t2.cid = '002'


);


7、查询学过“叶平”老师所教的所有课的同学的学号、姓名;


select sid,sname from t_student


where sid in


(


select sid from t_score t1 ,t_course t2,t_teacher t3


where t1.cid=t2.cid


and t3.tid=t2.tid


and t3.tname = '叶平'


group by sid


having count(t1.cid)=(


select count(cid) from t_course t1,t_teacher t2


where t2.tid=t1.tid and t2.tname = '叶平'


)


);


8、查询“001”课程比“002”课程成绩高的所有同学的学号、姓名;


Select sid,sname from


(


select t1.sid,t1.sname,t2.grade ,


(


select grade from t_score t3


where t3.sid = t1.sid and t3.cid = '002'


) grade2


from t_student t1, t_score t2


where t1sid = t2.sid and t2.cid = '001'


) S_2


where grade 2 < grade ;


9、查询所有课程成绩小于60分的同学的学号、姓名;


select sid,sname from t_student


where sid not in


(


select t1.sid from t_student t1, t_score t2


where t1.sid = t2.sid and t2.grade >60


);


10、查询没有学全所有课的同学的学号、姓名;


select t1.sid,t1.sname from Student t1, t_score t2


where t1.sid = t2.sid


group by t1.sid,t1.sname


having count(t2.cid) < (select count(cid) from t_course);


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;


select sid,sname from t_student t1, t_score t2


where t1.sid = t2.sid


and cid in (select cid from t_score where sid = '1001');


12、查询至少学过学号为“001”同学所有一门课的其他同学学号和姓名;


select distinct t2.sid,t1.sname from t_student t1, t_score t2


where t1.sid = t2.sid


and cid in (select cid from t_score where sid = '001');


13、把“ t_score”表中“叶平”老师教的课的成绩都更改为此课程的平均成绩;


update t_score t4 set grade =(select avg( t3.grade ) from t_score t3 where t3.cid= t4.cid )


from t_course t1,t_teacher t2


where t1.cid = t4.cid


and t1.tid = t2.tid


and t2.tname = '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 sid from t_score


where cid in (select cid from t_score where sid = '1002')


group by sid


having count(*)=(select count(*) from t_score where sid = '1002');


15、删除学习“叶平”老师课的 t_score表记录;


delect t_score from t_course t1 ,t_teacher t2


Where t1.cid = t2.cid


and t1.tid = t2.tid


and t2.tname = '叶平';


16、向 t_score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、2、


号课的平均成绩;


insert t_score


select sid,'002',(Select avg(grade ) from t_score where cid = '002')


from t_student


where sid not in (Select sid from t_score where cid = '002');


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 sid as 学生ID,


(SELECT grade FROM t_score WHERE sid=t.sid AND cid='004') AS 数据库,


(SELECT grade FROM t_score WHERE sid=t.sid AND cid='001') AS 企业管理,


(SELECT grade FROM t_score WHERE sid=t.sid AND cid='006') AS 英语,


COUNT(*) AS 有效课程数,


AVG(t.grade ) AS 平均成绩


FROM t_score AS t


GROUP BY sid


ORDER BY avg(t.grade )


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 t1.cid As 课程ID,t1.grade AS 最高分,t2.grade AS 最低分


FROM t_score t1 , t_score t2


WHERE t1.cid = t2.cid


and t1.grade = (


SELECT MAX(tt1.grade ) FROM t_score tt1,t_student tt2


WHERE t1.cid = tt1.cid and tt2.sid = tt1.sid


GROUP BY tt1.cid


)


AND t2.grade = (


SELECT MIN(tt3.grade ) FROM t_score AS tt3


WHERE t2.cid = tt3.cid GROUP BY tt2.cid


);


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


SELECT t.cid AS 课程号,max(course.cname)AS 课程名,isnull(AVG(grade ),0) AS 平均成绩 ,


100 * SUM(CASE WHEN isnull(grade ,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数


FROM t_score t1,t_course t2


where t1.cid = t2.cid


GROUP BY t1.cid


ORDER BY 100 * SUM(CASE WHEN isnull(grade ,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) 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


SUM(


CASE WHEN cid = '001'


THEN grade ELSE 0 END)/SUM(CASE cid WHEN '001'


THEN 1 ELSE 0 END


) AS 企业管理平均分 ,


100 * SUM(


CASE WHEN cid = '001' AND grade >= 60


THEN 1 ELSE 0 END)/SUM(CASE WHEN cid = '001'


THEN 1 ELSE 0 END


) AS 企业管理及格百分数 FROM t_score


21、查询不同老师所教不同课程平均分从高到低显示


SELECT max(t3.tid) AS 教师ID,MAX(t3.tname) AS 教师姓名,


T2.cid AS 课程ID,MAX(t2.cname) AS 课程名称,AVG(grade ) AS 平均成绩


FROM t_score AS t1,t_course AS t2 ,t_teacher AS t3


where t1.cid = t2.cid and t2.tid = t3.tid


GROUP BY t2.cid


ORDER BY AVG(grade ) 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)


[学生ID],[学生姓名],企业管理,马克思,UML,数据库,平均成绩


SELECT DISTINCT top 3 t_score.sid As 学生学号,Student.Sname AS 学生姓名 ,


T1.grade AS 企业管理, T2.grade AS 马克思, T3.grade AS UML,


T4.grade AS 数据库,ISNULL(T1.grade ,0) + ISNULL(T2.grade ,0) + ISNULL(T3.grade ,0) + ISNULL(T4.grade ,0) as 总分


FROM Student, t_score


LEFT JOIN t_score AS T1


ON t_score.sid = T1.sid AND T1.cid = '001'


LEFT JOIN t_score AS T2


ON t_score.sid = T2.sid AND T2.cid = '002'


LEFT JOIN t_score AS T3


ON t_score.sid = T3.sid AND T3.cid = '003'


LEFT JOIN t_score AS T4


ON t_score.sid = T4.sid AND T4.cid = '004'


WHERE student.sid= t_score.sid


and ISNULL(T1.grade ,0) + ISNULL(T2.grade ,0) + ISNULL(T3.grade ,0) + ISNULL(T4.grade ,0)


NOT IN (


SELECT DISTINCT TOP 15 WITH TIES ISNULL(T1.grade ,0) + ISNULL(T2.grade ,0) + ISNULL(T3.grade ,0) + ISNULL(T4.grade ,0)


FROM t_score


LEFT JOIN t_score AS T1


ON t_score.sid = T1.sid AND T1.cid = 'k1'


LEFT JOIN t_score AS T2


ON t_score.sid = T2.sid AND T2.cid = 'k2'


LEFT JOIN t_score AS T3


ON t_score.sid = T3.sid AND T3.cid = 'k3'


LEFT JOIN t_score AS T4


ON t_score.sid = T4.sid AND T4.cid = 'k4'


ORDER BY ISNULL(T1.grade ,0) + ISNULL(T2.grade ,0) + ISNULL(T3.grade ,0) + ISNULL(T4.grade ,0) DE t_score


);


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 t1.cid as 课程ID, t2.cname as 课程名称,


SUM(CASE WHEN t1.grade BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85],


SUM(CASE WHEN t1.grade BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 - 70],


SUM(CASE WHEN t1.grade BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 - 60],


SUM(CASE WHEN t1.grade < 60 THEN 1 ELSE 0 END) AS [60 -]


FROM t_score t1,t_course t2 where t1.cid = t2.cid


GROUP BY t1.cid,t2.cname;


24、查询学生平均成绩及其名次


SELECT


1+(


SELECT COUNT( distinct avggrade )


FROM (


SELECT sid,AVG(grade ) AS avggrade FROM t_score GROUP BY sid


) AS T1 WHERE avggrade > T2.avggrade ) as 名次,


sid as 学生学号,


avggrade


FROM (


SELECT sid,AVG(grade )as avggrade FROM t_score GROUP BY sid


) AS T2


ORDER BY avggrade desc;


25、查询各科成绩前三名的记录:(不考虑成绩并列情况)


SELECT t1.sid as 学生ID,t1.cid as 课程ID,grade as 分数


FROM t_score t1 WHERE grade IN (


SELECT TOP 3 grade FROM t_score t2 WHERE t1.cid = t2.cid ORDER BY grade DESC


)


ORDER BY t1.cid;


26、查询每门课程被选修的学生数


select cid,count(sid) from t_score group by cid;


27、查询出只选修了一门课程的全部学生的学号和姓名


select t1.sid,t2.sname,count(t1.cid) AS 选课数 from t_score t1,t_student t2


where t1.sid=t2.sid


group by t1.sid ,t2.sname


having count(t1.cid)=1;


28、查询男生、女生人数


Select count(ssex) as 男生人数 from t_student group by ssex having ssex='男';


Select count(ssex) as 女生人数 from t_student group by ssex having ssex='女';


29、查询姓“张”的学生名单


SELECT sname FROM t_student WHERE sname like '张%';


30、查询同名同性学生名单，并统计同名人数


select sname,count(*) from t-student group by sname having count(*)>1;


31、1981年出生的学生名单(注：Student表中Sage列的类型是datetime)


select sname, CONVERT(char(11),DATEPART(year,sage)) as age


from t_tudent


where CONVERT(char(11),DATEPART(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 cid,Avg(grade ) from t_score group by cid order by Avg(grade ),cid 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 t1.sname, t2.sid ,avg(t2.grade ) from t_student t1, t_score t2


where t1.sid=t2.sid group by t2.sid,t1.sname


having avg(t2.grade )>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 t1.sname,isnull(t2.grade ,0) from t_student t1, t_score t2,t_course t3


where t2.sid = t1.sid and t2.cid = t3.cid


and t3.cname='数据库'and t2.grade <60;


35、查询所有学生的选课情况;


SELECT t1.sid, t1.cid,t2.sname,t3.cname FROM t_score t1,t_student t2,t_course t3


where t1.sid = t2.sid and t1.cid = t3.cid ;


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 distinct t1.sid,t1.sname,t2.cid, t2.grade FROM t_student t1, t_score t2


WHERE t2.grade >=70 AND t2.sid = t1.sid;


37、查询不及格的课程，并按课程号从大到小排列


select cid from t_score where grade < 60 order by cid ;


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 t1.sid,t2.sname from t_score t1,t_student t2


where t1.sid = t2.sid and t1.grade > 80 and t1.cid = '003';


39、求选了课程的学生人数


select count(*) from t_score;


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 t1.sname,t2.grade from t_student t1, t_score t2,t_course t3,t_teacher t4


where t1.sid = t2.sid


and t2.cid = t3.cid


and t3.tid = t4.tid


and t4.Tname = '叶平'


and t2.grade = (select max(grade )from t_score where cid=t3.cid );


41、查询各个课程及相应的选修人数


select count(*) from t_score group by cid


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 distinct t1.sid,t2.grade from t_score t1 , t_score t2


where t1.grade = t2.grade and t1.cid <>t2.cid ;


43、查询每门功成绩最好的前两名


SELECT t1.sid as 学生ID,t1.cid as 课程ID,grade as 分数 FROM t_score t1


WHERE grade IN (


SELECT TOP 2 grade FROM t_score


WHERE t1.cid = cid ORDER BY grade DESC


)


ORDER BY t1.cid;


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，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 cid as 课程号,count(*) as 人数 from t_score


group by cid


order by count(*) desc,cid


45、检索至少选修两门课程的学生学号


select sid from t_score group by sid having count(*) > = 2


46、查询全部学生都选修的课程的课程号和课程名


select cid,cname from t_course where cid in (select cid from t_score group by cid)


47、查询没学过“叶平”老师讲授的任一门课程的学生姓名


select sname from t_student


where sid not in (


select sid from t_course t1,t_teacher t2, t_score t3


where t1.tid = t2.tid


and t3.cid =t 1.cid


and t2.tname = '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 sid,avg(isnull(grade ,0)) from t_score


where sid in (


select sid from t_score


where grade <60 group by sid having count(*)>2


)


group by sid;


49、检索“004”课程分数小于60，按分数降序排列的同学学号


select sid from t_score where cid='004'and grade <60 order by grade desc;


50、删除“002”同学的“001”课程的成绩


delete from t_score where sid='001'and cid = '001';




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