经典SQL面试题.docx
《经典SQL面试题.docx》由会员分享,可在线阅读,更多相关《经典SQL面试题.docx(14页珍藏版)》请在冰豆网上搜索。
![经典SQL面试题.docx](https://file1.bdocx.com/fileroot1/2023-2/25/573099e5-3db6-4126-9a3b-bec6b5a75911/573099e5-3db6-4126-9a3b-bec6b5a759111.gif)
经典SQL面试题
表
Student(Sid,Sname,Sage,Ssex)学生表
CREATETABLEstudent(
sidvarchar(10)NOTNULL,
sNamevarchar(20)DEFAULTNULL,
sAgedatetimeDEFAULT'1980-10-1223:
12:
36',
sSexvarchar(10)DEFAULTNULL,
PRIMARYKEY(sid)
)ENGINE=InnoDBDEFAULTCHARSET=utf8;
Course(Cid,Cname,Tid)课程表
CREATETABLEcourse(
cidvarchar(10)NOTNULL,
cNamevarchar(10)DEFAULTNULL,
tidint(20)DEFAULTNULL,
PRIMARYKEY(cid)
)ENGINE=InnoDBDEFAULTCHARSET=utf8;
SC(Sid,Cid,score)成绩表
CREATETABLEsc(
sidvarchar(10)DEFAULTNULL,
cidvarchar(10)DEFAULTNULL,
scoreint(10)DEFAULTNULL
)ENGINE=InnoDBDEFAULTCHARSET=utf8;
Teacher(Tid,Tname)教师表
CREATETABLEtaacher(
tidint(10)DEFAULTNULL,
tNamevarchar(10)DEFAULTNULL
)ENGINE=InnoDBDEFAULTCHARSET=utf8;
数据:
(MySQL)
insertintotaacher(tid,tName)values(1,'李老师'),(2,'何以琛'),(3,'叶平');
insertintostudent(sid,sName,sAge,sSex)values('1001','张三丰','1980-10-1223:
12:
36','男'),('1002','张无极','1995-10-1223:
12:
36','男'),('1003','李奎','1992-10-1223:
12:
36','女'),('1004','李元宝','1980-10-1223:
12:
36','女'),('1005','李世明','1981-10-1223:
12:
36','男'),('1006','赵六','1986-10-1223:
12:
36','男'),('1007','田七','1981-10-1223:
12:
36','女');
insertintosc(sid,cid,score)values('1','001',80),('1','002',60),('1','003',75),('2','001',85),('2','002',70),('3','004',100),('3','001',90),('3','002',55),('4','002',65),('4','003',60);
insertintocourse(cid,cName,tid)values('001','企业管理',3),('002','马克思',3),('003','UML',2),('004','数据库',1),('005','英语',1);
问题:
1、查询“001”课程比“002”课程成绩高的所有学生的学号;
selecta.Sidfrom(selectsid,scorefromSCwhereCid='001')a,(selectsid,score
fromSCwhereCid='002')b
wherea.score>b.scoreanda.sid=b.sid;
2、查询平均成绩大于60分的同学的学号和平均成绩;
selectSid,avg(score)
fromsc
groupbySidhavingavg(score)>60;
3、查询所有同学的学号、姓名、选课数、总成绩;
selectStudent.Sid,Student.Sname,count(SC.Cid),sum(score)
fromStudentleftOuterjoinSConStudent.Sid=SC.Sid
groupbyStudent.Sid,Sname
4、查询姓“李”的老师的个数;
selectcount(distinct(Tname))
fromTeacher
whereTnamelike'李%';
5、查询没学过“叶平”老师课的同学的学号、姓名;
selectStudent.Sid,Student.Sname
fromStudent
whereSidnotin(selectdistinct(SC.Sid)fromSC,Course,TeacherwhereSC.Cid=Course.CidandTeacher.Tid=Course.TidandTeacher.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;
selectStudent.Sid,Student.SnamefromStudent,SCwhereStudent.Sid=SC.SidandSC.Cid='001'andexists(Select*fromSCasSC_2whereSC_2.Sid=SC.SidandSC_2.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;
selectSid,Sname
fromStudent
whereSidin(selectSidfromSC,Course,TeacherwhereSC.Cid=Course.CidandTeacher.Tid=Course.TidandTeacher.Tname='叶平'groupbySidhavingcount(SC.Cid)=(selectcount(Cid)fromCourse,TeacherwhereTeacher.Tid=Course.TidandTname='叶平'));
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;
SelectSid,Snamefrom(selectStudent.Sid,Student.Sname,score,(selectscorefromSCSC_2whereSC_2.Sid=Student.SidandSC_2.Cid='002')score2
fromStudent,SCwhereStudent.Sid=SC.SidandCid='001')S_2wherescore29、查询所有课程成绩小于60分的同学的学号、姓名;
selectSid,Sname
fromStudent
whereSidnotin(selectStudent.SidfromStudent,SCwhereS.Sid=SC.Sidandscore>60);
10、查询没有学全所有课的同学的学号、姓名;
selectStudent.Sid,Student.Sname
fromStudent,SC
whereStudent.Sid=SC.SidgroupbyStudent.Sid,Student.Snamehavingcount(Cid)<(selectcount(Cid)fromCourse);
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;
selectSid,SnamefromStudent,SCwhereStudent.Sid=SC.SidandCidinselectCidfromSCwhereSid='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;
selectdistinctSC.Sid,Sname
fromStudent,SC
whereStudent.Sid=SC.SidandCidin(selectCidfromSCwhereSid='001');
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;
updateSCsetscore=(selectavg(SC_2.score)
fromSCSC_2
whereSC_2.Cid=SC.Cid)fromCourse,TeacherwhereCourse.Cid=SC.CidandCourse.Tid=Teacher.TidandTeacher.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;
selectSidfromSCwhereCidin(selectCidfromSCwhereSid='1002')
groupbySidhavingcount(*)=(selectcount(*)fromSCwhereSid='1002');
15、删除学习“叶平”老师课的SC表记录;
DelectSC
fromcourse,Teacher
whereCourse.Cid=SC.CidandCourse.Tid=Teacher.TidandTname='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、2号课的平均成绩;
InsertSCselectSid,'002',(Selectavg(score)
fromSCwhereCid='002')fromStudentwhereSidnotin(SelectSidfromSCwhereCid='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
SELECTSidas学生ID
(SELECTscoreFROMSCWHERESC.Sid=t.SidANDCid='004')AS数据库
(SELECTscoreFROMSCWHERESC.Sid=t.SidANDCid='001')AS企业管理
(SELECTscoreFROMSCWHERESC.Sid=t.SidANDCid='006')AS英语
COUNT(*)AS有效课程数,AVG(t.score)AS平均成绩
FROMSCASt
GROUPBYSid
ORDERBYavg(t.score)
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
SELECTL.CidAs课程ID,L.scoreAS最高分,R.scoreAS最低分
FROMSCL,SCASR
WHEREL.Cid=R.Cidand
L.score=(SELECTMAX(IL.score)
FROMSCASIL,StudentASIM
WHEREL.Cid=IL.CidandIM.Sid=IL.Sid
GROUPBYIL.Cid)
AND
R.Score=(SELECTMIN(IR.score)
FROMSCASIR
WHERER.Cid=IR.Cid
GROUPBYIR.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
SELECTt.CidAS课程号,max(course.Cname)AS课程名,isnull(AVG(score),0)AS平均成绩
100*SUM(CASEWHENisnull(score,0)>=60THEN1ELSE0END)/COUNT(*)AS及格百分数
FROMSCT,Course
wheret.Cid=course.Cid
GROUPBYt.Cid
ORDERBY100*SUM(CASEWHENisnull(score,0)>=60THEN1ELSE0END)/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)
SELECTSUM(CASEWHENCid='001'THENscoreELSE0END)/SUM(CASECidWHEN'001'THEN1ELSE0END)AS企业管理平均分
100*SUM(CASEWHENCid='001'ANDscore>=60THEN1ELSE0END)/SUM(CASEWHENCid='001'THEN1ELSE0END)AS企业管理及格百分数
SUM(CASEWHENCid='002'THENscoreELSE0END)/SUM(CASECidWHEN'002'THEN1ELSE0END)AS马克思平均分
100*SUM(CASEWHENCid='002'ANDscore>=60THEN1ELSE0END)/SUM(CASEWHENCid='002'THEN1ELSE0END)AS马克思及格百分数
SUM(CASEWHENCid='003'THENscoreELSE0END)/SUM(CASECidWHEN'003'THEN1ELSE0END)ASUML平均分
100*SUM(CASEWHENCid='003'ANDscore>=60THEN1ELSE0END)/SUM(CASEWHENCid='003'THEN1ELSE0END)ASUML及格百分数
SUM(CASEWHENCid='004'THENscoreELSE0END)/SUM(CASECidWHEN'004'THEN1ELSE0END)AS数据库平均分
100*SUM(CASEWHENCid='004'ANDscore>=60THEN1ELSE0END)/SUM(CASEWHENCid='004'THEN1ELSE0END)AS数据库及格百分数
FROMSC
21、查询不同老师所教不同课程平均分从高到低显示
SELECTmax(Z.Tid)AS教师ID,MAX(Z.Tname)AS教师姓名,C.CidAS课程ID,MAX(C.Cname)AS课程名称,AVG(Score)AS平均成绩
FROMSCAST,CourseASC,TeacherASZ
whereT.Cid=C.CidandC.Tid=Z.Tid
GROUPBYC.Cid
ORDERBYAVG(Score)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
SELECTDISTINCTtop3
SC.SidAs学生学号,
Student.SnameAS学生姓名,
T1.scoreAS企业管理,
T2.scoreAS马克思,
T3.scoreASUML,
T4.scoreAS数据库,
ISNULL(T1.score,0)+ISNULL(T2.score,0)+ISNULL(T3.score,0)+ISNULL(T4.score,0)as总分
FROMStudent,SCLEFTJOINSCAST1
ONSC.Sid=T1.SidANDT1.Cid='001'
LEFTJOINSCAST2
ONSC.Sid=T2.SidANDT2.Cid='002'
LEFTJOINSCAST3
ONSC.Sid=T3.SidANDT3.Cid='003'
LEFTJOINSCAST4
ONSC.Sid=T4.SidANDT4.Cid='004'
WHEREstudent.Sid=SC.Sidand
ISNULL(T1.score,0)+ISNULL(T2.score,0)+ISNULL(T3.score,0)+ISNULL(T4.score,0)
NOTIN
(SELECT
DISTINCT
TOP15WITHTIES
ISNULL(T1.score,0)+ISNULL(T2.score,0)+ISNULL(T3.score,0)+ISNULL(T4.score,0)
FROMsc
LEFTJOINscAST1
ONsc.Sid=T1.SidANDT1.Cid='k1'
LEFTJOINscAST2
ONsc.Sid=T2.SidANDT2.Cid='k2'
LEFTJOINscAST3
ONsc.Sid=T3.SidANDT3.Cid='k3'
LEFTJOINscAST4
ONsc.Sid=T4.SidANDT4.Cid='k4'
ORDERBYISNULL(T1.score,0)+ISNULL(T2.score,0)+ISNULL(T3.score,0)+ISNULL(T4.score,0)DESC);
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]
SELECTSC.Cidas课程ID,Cnameas课程名称
SUM(CASEWHENscoreBETWEEN85AND100THEN1ELSE0END)AS[100-85]
SUM(CASEWHENscoreBETWEEN70AND85THEN1ELSE0END)AS[85-70]
SUM(CASEWHENscoreBETWEEN60AND70THEN1ELSE0END)AS[70-60]
SUM(CASEWHENscore<60THEN1ELSE0END)AS[60-]
FROMSC,Course
whereSC.Cid=Course.Cid
GROUPBYSC.Cid,Cname;
24、查询学生平均成绩及其名次
SELECT1+(SELECTCOUNT(distinct平均成绩)
FROM(SELECTSid,AVG(score)AS平均成绩
FROMSC
GROUPBYSid
)AST1
WHERE平均成绩>T2.平均成绩)as名次,
Sidas学生学号,平均成绩
FROM(SELECTSid,AVG(score)平均成绩
FROMSC
GROUPBYSid
)AST2
ORDERBY平均成绩desc;
25、查询各科成绩前三名的记录:
(不考虑成绩并列情况)
SELECTt1.Sidas学生ID,t1.Cidas课程ID,Scoreas分数
FROMSCt1
WHEREscoreIN(SELECTTOP3score
FROMSC
WHEREt1.Cid=Cid
ORDERBYscoreDESC
)
ORDERBYt1.Cid;
26、查询每门课程被选修的学生数
selectcid,count(Sid)fromscgroupbyCid;
27、查询出只选修了一门课程的全部学生的学号和姓名
selectSC.Sid,Student.Sname,count(Cid)AS选课数
fromSC,Student
whereSC.Sid=Student.SidgroupbySC.Sid,Student.Snamehavingcount(Cid)=1;
28、查询男生、女生人数
Selectcount(Ssex)as男生人数fromStudentgroupbySsexhavingSsex='男';
Selectcount(Ssex)as女生人数fromStudentgroupbySsexhavingSsex='女';
29、查询姓“张”的学生名单
SELECTSnameFROMStudentWHERESnamelike'张%';
30、查询同名同性学生名单,并统计同名人数
selectSname,count(*)fromStudentgroupbySnamehavingcount(*)>1;;
31、1981年出生的学生名单(注:
Student表中Sage列的类型是datetime)
selectSname,CONVERT(char(11),DATEPART(year,Sage))asage
fromstudent
whereCONVERT(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
SelectCid,Avg(score)fromSCgroupbyCidorderbyAvg(score),CidDESC;
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
selectSname,SC.Sid,avg(score)
fromStudent,SC
whereStudent.Sid=SC.SidgroupbySC.Sid,Snamehavingavg(score)>