SQL语言 - SQL语句练习
约 2632 字大约 9 分钟
SQL语言 - SQL语句练习
在上文学习了SQL的基本语法以后，本文将通过最经典的“教师-学生-成绩”表来帮助你练习SQL。@pdai
构建如下表结构
还有一个Grade表，在如下的练习中体现
插入数据
下面表SQL和相关测试数据是我Dump出来的
-- MySQL dump 10.13 Distrib 5.7.17, for macos10.12 (x86_64)
--
-- Host: localhost Database: learn_sql_pdai_tech
-- ------------------------------------------------------
-- Server version 5.7.28
/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
/*!40103 SET TIME_ZONE='+00:00' */;
/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
--
-- Table structure for table `COURSE`
--
DROP TABLE IF EXISTS `COURSE`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `COURSE` (
`CNO` varchar(5) NOT NULL,
`CNAME` varchar(10) NOT NULL,
`TNO` varchar(10) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = @saved_cs_client */;
--
-- Dumping data for table `COURSE`
--
LOCK TABLES `COURSE` WRITE;
/*!40000 ALTER TABLE `COURSE` DISABLE KEYS */;
INSERT INTO `COURSE` VALUES ('3-105','计算机导论','825'),('3-245','操作系统','804'),('6-166','数据电路','856'),('9-888','高等数学','100');
/*!40000 ALTER TABLE `COURSE` ENABLE KEYS */;
UNLOCK TABLES;
--
-- Table structure for table `SCORE`
--
DROP TABLE IF EXISTS `SCORE`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `SCORE` (
`SNO` varchar(3) NOT NULL,
`CNO` varchar(5) NOT NULL,
`DEGREE` decimal(10,1) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = @saved_cs_client */;
--
-- Dumping data for table `SCORE`
--
LOCK TABLES `SCORE` WRITE;
/*!40000 ALTER TABLE `SCORE` DISABLE KEYS */;
INSERT INTO `SCORE` VALUES ('103','3-245',86.0),('105','3-245',75.0),('109','3-245',68.0),('103','3-105',92.0),('105','3-105',88.0),('109','3-105',76.0),('101','3-105',64.0),('107','3-105',91.0),('101','6-166',85.0),('107','6-106',79.0),('108','3-105',78.0),('108','6-166',81.0);
/*!40000 ALTER TABLE `SCORE` ENABLE KEYS */;
UNLOCK TABLES;
--
-- Table structure for table `STUDENT`
--
DROP TABLE IF EXISTS `STUDENT`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `STUDENT` (
`SNO` varchar(3) NOT NULL,
`SNAME` varchar(4) NOT NULL,
`SSEX` varchar(2) NOT NULL,
`SBIRTHDAY` datetime DEFAULT NULL,
`CLASS` varchar(5) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = @saved_cs_client */;
--
-- Dumping data for table `STUDENT`
--
LOCK TABLES `STUDENT` WRITE;
/*!40000 ALTER TABLE `STUDENT` DISABLE KEYS */;
INSERT INTO `STUDENT` VALUES ('108','曾华','男','1977-09-01 00:00:00','95033'),('105','匡明','男','1975-10-02 00:00:00','95031'),('107','王丽','女','1976-01-23 00:00:00','95033'),('101','李军','男','1976-02-20 00:00:00','95033'),('109','王芳','女','1975-02-10 00:00:00','95031'),('103','陆君','男','1974-06-03 00:00:00','95031');
/*!40000 ALTER TABLE `STUDENT` ENABLE KEYS */;
UNLOCK TABLES;
--
-- Table structure for table `TEACHER`
--
DROP TABLE IF EXISTS `TEACHER`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `TEACHER` (
`TNO` varchar(3) NOT NULL,
`TNAME` varchar(4) NOT NULL,
`TSEX` varchar(2) NOT NULL,
`TBIRTHDAY` datetime NOT NULL,
`PROF` varchar(6) DEFAULT NULL,
`DEPART` varchar(10) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = @saved_cs_client */;
--
-- Dumping data for table `TEACHER`
--
LOCK TABLES `TEACHER` WRITE;
/*!40000 ALTER TABLE `TEACHER` DISABLE KEYS */;
INSERT INTO `TEACHER` VALUES ('804','李诚','男','1958-12-02 00:00:00','副教授','计算机系'),('856','张旭','男','1969-03-12 00:00:00','讲师','电子工程系'),('825','王萍','女','1972-05-05 00:00:00','助教','计算机系'),('831','刘冰','女','1977-08-14 00:00:00','助教','电子工程系');
/*!40000 ALTER TABLE `TEACHER` ENABLE KEYS */;
UNLOCK TABLES;
/*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
-- Dump completed on 2020-02-06 18:18:25
相关练习
- 1、 查询Student表中的所有记录的Sname、Ssex和Class列。
select SNAME, SSEX, CLASS from STUDENT;
- 2、 查询教师所有的单位即不重复的Depart列。
select distinct DEPART from TEACHER;
- 3、 查询Student表的所有记录。
select * from STUDENT;
- 4、 查询Score表中成绩在60到80之间的所有记录。
select *
from SCORE
where DEGREE > 60 and DEGREE < 80;
- 5、 查询Score表中成绩为85，86或88的记录。
select *
from SCORE
where DEGREE = 85 or DEGREE = 86 or DEGREE = 88;
- 6、 查询Student表中“95031”班或性别为“女”的同学记录。
select *
from STUDENT
where CLASS = '95031' or SSEX = '女';
- 7、 以Class降序查询Student表的所有记录。
select *
from STUDENT
order by CLASS desc;
- 8、 以Cno升序、Degree降序查询Score表的所有记录。
select *
from SCORE
order by CNO asc, DEGREE desc;
- 9、 查询“95031”班的学生人数。
select count(*)
from STUDENT
where CLASS = '95031';
- 10、查询Score表中的最高分的学生学号和课程号。
select
sno,
CNO
from SCORE
where DEGREE = (
select max(DEGREE)
from SCORE
);
- 11、查询‘3-105’号课程的平均分。
select avg(DEGREE)
from SCORE
where CNO = '3-105';
- 12、查询Score表中至少有5名学生选修的并以3开头的课程的平均分数。
select
avg(DEGREE),
CNO
from SCORE
where cno like '3%'
group by CNO
having count(*) > 5;
- 13、查询最低分大于70，最高分小于90的Sno列。
select SNO
from SCORE
group by SNO
having min(DEGREE) > 70 and max(DEGREE) < 90;
- 14、查询所有学生的Sname、Cno和Degree列。
select
SNAME,
CNO,
DEGREE
from STUDENT, SCORE
where STUDENT.SNO = SCORE.SNO;
- 15、查询所有学生的Sno、Cno和Degree列。
select
SCORE.SNO,
CNO,
DEGREE
from STUDENT, SCORE
where STUDENT.SNO = SCORE.SNO;
- 16、查询所有学生的Sname、Cname和Degree列。
SELECT
A.SNAME,
B.CNAME,
C.DEGREE
FROM STUDENT A
JOIN (COURSE B, SCORE C)
ON A.SNO = C.SNO AND B.CNO = C.CNO;
- 17、查询“95033”班所选课程的平均分。
select avg(DEGREE)
from SCORE
where sno in (select SNO
from STUDENT
where CLASS = '95033');
- 18、假设使用如下命令建立了一个grade表:
create table grade (
low numeric(3, 0),
upp numeric(3),
rank char(1)
);
insert into grade values (90, 100, 'A');
insert into grade values (80, 89, 'B');
insert into grade values (70, 79, 'C');
insert into grade values (60, 69, 'D');
insert into grade values (0, 59, 'E');
- 现查询所有同学的Sno、Cno和rank列。
SELECT
A.SNO,
A.CNO,
B.RANK
FROM SCORE A, grade B
WHERE A.DEGREE BETWEEN B.LOW AND B.UPP
ORDER BY RANK;
- 19、查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。
select *
from SCORE
where CNO = '3-105' and DEGREE > ALL (
select DEGREE
from SCORE
where SNO = '109'
);
- 20、查询score中选学一门以上课程的同学中分数为非最高分成绩的学生记录
select * from STUDENT where SNO
in (select SNO
from SCORE
where DEGREE < (select MAX(DEGREE) from SCORE)
group by SNO
having count(*) > 1);
- 21、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。
select *
from SCORE
where CNO = '3-105' and DEGREE > ALL (
select DEGREE
from SCORE
where SNO = '109'
);
- 22、查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。
select
SNO,
SNAME,
SBIRTHDAY
from STUDENT
where year(SBIRTHDAY) = (
select year(SBIRTHDAY)
from STUDENT
where SNO = '108'
);
- 23、查询“张旭“教师任课的学生成绩。
select *
from SCORE
where cno = (
select CNO
from COURSE
inner join TEACHER on COURSE.TNO = TEACHER.TNO and TNAME = '张旭'
);
- 24、查询选修某课程的同学人数多于5人的教师姓名。
select TNAME
from TEACHER
where TNO = (
select TNO
from COURSE
where CNO = (select CNO
from SCORE
group by CNO
having count(SNO) > 5)
);
- 25、查询95033班和95031班全体学生的记录。
select *
from STUDENT
where CLASS in ('95033', '95031');
- 26、查询存在有85分以上成绩的课程Cno.
select cno
from SCORE
group by CNO
having MAX(DEGREE) > 85;
- 27、查询出“计算机系“教师所教课程的成绩表。
select *
from SCORE
where CNO in (select CNO
from TEACHER, COURSE
where DEPART = '计算机系' and COURSE.TNO = TEACHER.TNO);
- 28、查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof
select
tname,
prof
from TEACHER
where depart = '计算机系' and prof not in (
select prof
from TEACHER
where depart = '电子工程系'
);
- 29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
select
CNO,
SNO,
DEGREE
from SCORE
where CNO = '3-105' and DEGREE > any (
select DEGREE
from SCORE
where CNO = '3-245'
)
order by DEGREE desc;
- 30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.
SELECT *
FROM SCORE
WHERE CNO = '3-105' AND DEGREE > ALL (
SELECT DEGREE
FROM SCORE
WHERE CNO = '3-245'
)
ORDER by DEGREE desc;
- 31、查询所有教师和同学的name、sex和birthday.
select
TNAME name,
TSEX sex,
TBIRTHDAY birthday
from TEACHER
union
select
sname name,
SSEX sex,
SBIRTHDAY birthday
from STUDENT;
- 32、查询所有“女”教师和“女”同学的name、sex和birthday.
select
TNAME name,
TSEX sex,
TBIRTHDAY birthday
from TEACHER
where TSEX = '女'
union
select
sname name,
SSEX sex,
SBIRTHDAY birthday
from STUDENT
where SSEX = '女';
- 33、查询成绩比该课程平均成绩低的同学的成绩表。
SELECT A.*
FROM SCORE A
WHERE DEGREE < (SELECT AVG(DEGREE)
FROM SCORE B
WHERE A.CNO = B.CNO);
- 34、查询所有任课教师的Tname和Depart.
select
TNAME,
DEPART
from TEACHER a
where exists(select *
from COURSE b
where a.TNO = b.TNO);
- 35、查询所有未讲课的教师的Tname和Depart.
select
TNAME,
DEPART
from TEACHER a
where tno not in (select tno
from COURSE);
- 36、查询至少有2名男生的班号。
select CLASS
from STUDENT
where SSEX = '男'
group by CLASS
having count(SSEX) > 1;
- 37、查询Student表中不姓“王”的同学记录。
select *
from STUDENT
where SNAME not like "王%";
- 38、查询Student表中每个学生的姓名和年龄。
select
SNAME,
year(now()) - year(SBIRTHDAY)
from STUDENT;
- 39、查询Student表中最大和最小的Sbirthday日期值。
select min(SBIRTHDAY) birthday
from STUDENT
union
select max(SBIRTHDAY) birthday
from STUDENT;
- 40、以班号和年龄从大到小的顺序查询Student表中的全部记录。
select *
from STUDENT
order by CLASS desc, year(now()) - year(SBIRTHDAY) desc;
- 41、查询“男”教师及其所上的课程。
select *
from TEACHER, COURSE
where TSEX = '男' and COURSE.TNO = TEACHER.TNO;
- 42、查询最高分同学的Sno、Cno和Degree列。
select
sno,
CNO,
DEGREE
from SCORE
where DEGREE = (select max(DEGREE)
from SCORE);
- 43、查询和“李军”同性别的所有同学的Sname.
select sname
from STUDENT
where SSEX = (select SSEX
from STUDENT
where SNAME = '李军');
- 44、查询和“李军”同性别并同班的同学Sname.
select sname
from STUDENT
where (SSEX, CLASS) = (select
SSEX,
CLASS
from STUDENT
where SNAME = '李军');
- 45、查询所有选修“计算机导论”课程的“男”同学的成绩表
select *
from SCORE, STUDENT
where SCORE.SNO = STUDENT.SNO and SSEX = '男' and CNO = (
select CNO
from COURSE
where CNAME = '计算机导论');
- 46、使用游标方式来同时查询每位同学的名字，他所选课程及成绩。
declare
cursor student_cursor is
select S.SNO,S.SNAME,C.CNAME,SC.DEGREE as DEGREE
from STUDENT S, COURSE C, SCORE SC
where S.SNO=SC.SNO
and SC.CNO=C.CNO;
student_row student_cursor%ROWTYPE;
begin
open student_cursor;
loop
fetch student_cursor INTO student_row;
exit when student_cursor%NOTFOUND;
dbms_output.put_line( student_row.SNO || '' ||
student_row.SNAME|| '' || student_row.CNAME || '' ||
student_row.DEGREE);
end loop;
close student_cursor;
END;
/
- 47、 声明触发器指令，每当有同学转换班级时执行触发器显示当前和之前所在班级。
CREATE OR REPLACE TRIGGER display_class_changes
AFTER DELETE OR INSERT OR UPDATE ON student
FOR EACH ROW
WHEN (NEW.sno > 0)
BEGIN
dbms_output.put_line('Old class: ' || :OLD.class);
dbms_output.put_line('New class: ' || :NEW.class);
END;
/
Update student
set class=95031
where sno=109;
- 48、 删除已设置的触发器指令
DROP TRIGGER display_class_changes;