CREATE TABLE student_t(

sno Char(7) PRIMARY KEY,--学号

sname Varchar(20) NOT NULL,--姓名

ssex CHAR(2) NOT NULL, --性别

sage Smallint, --年龄

CLON CHAR(5) --学生所在班级的编号

);

CREATE TABLE course_t(

cno CHAR(1) PRIMARY KEY, --课程编号

cname Varchar(20) NOT NULL, --课程名称

credit SMALLINT -- 学分

);

CREATE TABLE CLASS_t(

clno CHAR(5) PRIMARY KEY, --班级号

speciality VARCHAR(20) NOT NULL, --编辑所在专业

inyear CHAR(4) NOT NULL, --入校年份

cNUM INTEGER, -- 班级人数

MONITOR_no CHAR(7) -- 班长学号

);

CREATE TABLE grade_t(

sno char(7), --学号

cno CHAR(1) NOT NULL, --课程号

gmark NUMERIC(4,1) --成绩

);

INSERT INTO student_t (sno,sname,ssex,sage, CLON) VALUES ('2000101','李勇',  '男', 20,'00311');

INSERT INTO student_t (sno,sname,ssex,sage, CLON) VALUES ('2000102','刘诗晨','女', 19,'00311');

INSERT INTO student_t (sno,sname,ssex,sage, CLON) VALUES ('2000103','王一鸣','男', 20,'00312');

INSERT INTO student_t (sno,sname,ssex,sage, CLON) VALUES ('2000104','张婷婷','女', 21,'00312');

INSERT INTO student_t (sno,sname,ssex,sage, CLON) VALUES ('2001101','李勇敏','女', 19,'01311');

INSERT INTO student_t (sno,sname,ssex,sage, CLON) VALUES ('2001102','贾向东','男', 22,'01311');

INSERT INTO student_t (sno,sname,ssex,sage, CLON) VALUES ('2001103','陈宝玉','男', 20,'01311');

INSERT INTO student_t (sno,sname,ssex,sage, CLON) VALUES ('2001104','张逸凡','男', 21,'01311');

--增加以下这条数据目的是为了12.9查询到数据

INSERT INTO student_t (sno,sname,ssex,sage, CLON) VALUES ('2000105','折挺',  '男', 20,'00311');

INSERT INTO course_t ( cno,cname,credit) VALUES ('1','数据库',      4);

INSERT INTO course_t ( cno,cname,credit) VALUES ('2','离散数学',    3);

INSERT INTO course_t ( cno,cname,credit) VALUES ('3','管理信息系统',2);

INSERT INTO course_t ( cno,cname,credit) VALUES ('4','操作系统',    4);

INSERT INTO course_t ( cno,cname,credit) VALUES ('5','数据结构',    4);

INSERT INTO course_t ( cno,cname,credit) VALUES ('6','数据处理',    2);

INSERT INTO course_t ( cno,cname,credit) VALUES ('7','C语言',       4);

INSERT INTO CLASS_t (clno, speciality,inyear,cNUM,MONITOR_no) VALUES ('00311','计算机软件', '2000',120, '2000101');

INSERT INTO CLASS_t (clno, speciality,inyear,cNUM,MONITOR_no) VALUES ('00312','计算机应用', '2000',140, '2000103');

INSERT INTO CLASS_t (clno, speciality,inyear,cNUM,MONITOR_no) VALUES ('01311','计算机软件', '2001',220, '2001103');

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000101','1', 92);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000101','3', 88);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000101','5', 86);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000102','1', 78);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000102','6', 55);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000103','3', 65);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000103','6', 78);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000103','5', 66);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000104','1', 54);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000104','6', 83);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2001101','2', 70);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2001101','4', 65);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2001102','2', 80);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2001102','4', 90);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000103','1', 83);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000103','2', 76);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000103','4', 56);

INSERT INTO grade_t (sno, cno,gmark) VALUES ('2000103','7', 88);

--12.1 找出所有被学生选修了的课程号

SELECT DISTINCT cno FROM  grade_t gt ORDER BY gt.cno;

--12.2 找出01311班女学生的个人信息

SELECT * FROM student_t stu WHERE stu.clon = '01311' AND stu.ssex = '女';

--12.3 找出01311班和01312班的学生姓名、性别、出生年份

SELECT STU.SNAME,

STU.SSEX,

(TO_DATE(TO_CHAR(SYSDATE, 'YYYY/MM/DD'), 'YYYY/MM/DD') - STU.SAGE) AS 出生年份

FROM STUDENT_T STU

WHERE STU.CLON IN ('01311', '01312');

--12.4 找出所有姓李的学生的个人信息

SELECT * FROM student_t stu WHERE stu.sname LIKE '李%';

--12.5 找出学生李勇所在班级的学生人数

SELECT ct.cnum FROM student_t stu JOIN class_t ct ON stu.clon = ct.clno WHERE stu.sname = '李勇';

--或者是子查询(首先查询出李勇所在的班级号，注意要用distinct,防止有多个李勇报错)

SELECT  ct.cnum FROM class_t ct WHERE ct.clno = (SELECT DISTINCT stu.clon FROM student_t stu WHERE stu.sname = '李勇');

--12.6 找出课程名为操作系统的平均成绩、最高分、最低分

SELECT to_char(AVG(GT.GMARK),'99999999999999.99') AS 平均成绩,

MAX(GT.GMARK) AS 最高分,

MIN(GT.GMARK) AS 最低分

FROM COURSE_T COU JOIN GRADE_T GT ON COU.CNO = GT.CNO

WHERE COU.CNAME = '操作系统';

--12.7 找出选修了课程的学生人数

SELECT COUNT(1) FROM (SELECT DISTINCT gt.sno FROM grade_t gt);

--或者

SELECT count(1) FROM (SELECT gt.sno, COUNT(gt.sno) FROM grade_t gt GROUP BY gt.sno);

--12.8 找出选修了课程为操作系统的学生人数

SELECT COUNT(1) FROM course_t ct JOIN grade_t gt ON ct.cno = gt.cno WHERE ct.cname = '操作系统';

--12.9 找出2000级计算机软件班的成绩为空的学生姓名

SELECT STU.SNAME

FROM STUDENT_T STU

LEFT JOIN CLASS_T CT ON STU.CLON = CT.CLNO

LEFT JOIN grade_t gt ON gt.sno = stu.sno

WHERE CT.INYEAR = '2000'

AND CT.SPECIALITY = '计算机软件'

AND gt.gmark IS NULL;

--13.1 找出与李勇在同一个班级的学生信息

SELECT * FROM student_t stu WHERE stu.clon = (SELECT clon  FROM student_t WHERE sname = '李勇');

--13.2 找出所有与学生李勇有相同选修课程的学生信息

SELECT DISTINCT stu.*

FROM STUDENT_T STU

JOIN GRADE_T GT

ON STU.SNO = GT.SNO

WHERE GT.CNO IN

(SELECT GT.CNO

FROM GRADE_T

WHERE SNO =

(SELECT SNO FROM STUDENT_T WHERE SNAME = '李勇'));

--13.3 找出年龄介于学生李勇和25岁之间的学生的信息

SELECT * FROM student_t stu WHERE stu.sage BETWEEN (SELECT sage FROM student_t WHERE sname = '李勇') AND 25;

--13.4 找出选修了课程操作系统的学生的学号和姓名

SELECT stu.sno,stu.sname

FROM STUDENT_T STU

JOIN GRADE_T GT

ON STU.SNO = GT.SNO

JOIN COURSE_T COU

ON COU.CNO = GT.CNO

WHERE COU.CNAME = '操作系统';

--13.5 找出没有选修1号课程的所有学生姓名

SELECT stu.sname FROM student_t stu WHERE stu.sno NOT IN(SELECT gt.sno FROM grade_t gt WHERE gt.cno = 1);

--13.6 找出选修了全部课程的学生的姓名

SELECT stu.sname

FROM STUDENT_T STU

JOIN GRADE_T GT

ON STU.SNO = GT.SNO

GROUP BY STU.SNO,STU.SNAME

HAVING COUNT(1) = (SELECT COUNT(1) FROM COURSE_T);

--14.1 查询选修了3号课程的学生学号及其成绩，并按照成绩的降序排列

SELECT stu.sno,gt.gmark FROM STUDENT_T STU JOIN GRADE_T GT ON STU.SNO = GT.SNO WHERE gt.cno = 3 ORDER BY gt.gmark;

--14.2 查询全体学生信息，要求查询结果按班级号升序排列，同一班级学生按年龄降序排列

SELECT * FROM student_t stu ORDER BY stu.clon,stu.sage DESC;

--14.3 求每个课程号及相应的选课人数

SELECT cou.cno,COUNT(1) FROM course_t cou LEFT JOIN grade_t gt ON cou.cno = gt.cno GROUP BY cou.cno ORDER BY cou.cno;

--14.4 找出选修了3门以上课程的学生学号

SELECT gt.sno FROM grade_t gt GROUP BY gt.sno HAVING count(1)>3;

西安科技大学高新学院 计科1001班 折挺