标题 | SQL高级查询 |
范文 | 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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