diff --git a/notes/sql经典练习题.sql b/notes/sql经典练习题.sql
new file mode 100644
index 00000000..72965fa2
--- /dev/null
+++ b/notes/sql经典练习题.sql
@@ -0,0 +1,432 @@
+use fuxi;
+
+CREATE TABLE STUDENT
+(
+  SNO       VARCHAR(3) NOT NULL,
+  SNAME     VARCHAR(4) NOT NULL,
+  SSEX      VARCHAR(2) NOT NULL,
+  SBIRTHDAY DATETIME,
+  CLASS     VARCHAR(5)
+);
+
+CREATE TABLE COURSE
+(
+  CNO   VARCHAR(5)  NOT NULL,
+  CNAME VARCHAR(10) NOT NULL,
+  TNO   VARCHAR(10) NOT NULL
+);
+
+CREATE TABLE SCORE
+(
+  SNO    VARCHAR(3)     NOT NULL,
+  CNO    VARCHAR(5)     NOT NULL,
+  DEGREE NUMERIC(10, 1) NOT NULL
+);
+
+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),
+  DEPART    VARCHAR(10) NOT NULL
+);
+
+INSERT INTO STUDENT (SNO, SNAME, SSEX, SBIRTHDAY, CLASS) VALUES (108, '曾华'
+  , '男', '1977-09-01', 95033);
+INSERT INTO STUDENT (SNO, SNAME, SSEX, SBIRTHDAY, CLASS) VALUES (105, '匡明'
+  , '男', '1975-10-02', 95031);
+INSERT INTO STUDENT (SNO, SNAME, SSEX, SBIRTHDAY, CLASS) VALUES (107, '王丽'
+  , '女', '1976-01-23', 95033);
+INSERT INTO STUDENT (SNO, SNAME, SSEX, SBIRTHDAY, CLASS) VALUES (101, '李军'
+  , '男', '1976-02-20', 95033);
+INSERT INTO STUDENT (SNO, SNAME, SSEX, SBIRTHDAY, CLASS) VALUES (109, '王芳'
+  , '女', '1975-02-10', 95031);
+INSERT INTO STUDENT (SNO, SNAME, SSEX, SBIRTHDAY, CLASS) VALUES (103, '陆君'
+  , '男', '1974-06-03', 95031);
+
+INSERT INTO COURSE (CNO, CNAME, TNO) VALUES ('3-105', '计算机导论', 825);
+INSERT INTO COURSE (CNO, CNAME, TNO) VALUES ('3-245', '操作系统', 804);
+INSERT INTO COURSE (CNO, CNAME, TNO) VALUES ('6-166', '数据电路', 856);
+INSERT INTO COURSE (CNO, CNAME, TNO) VALUES ('9-888', '高等数学', 100);
+
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (103, '3-245', 86);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (105, '3-245', 75);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (109, '3-245', 68);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (103, '3-105', 92);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (105, '3-105', 88);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (109, '3-105', 76);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (101, '3-105', 64);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (107, '3-105', 91);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (101, '6-166', 85);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (107, '6-106', 79);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (108, '3-105', 78);
+INSERT INTO SCORE (SNO, CNO, DEGREE) VALUES (108, '6-166', 81);
+
+INSERT INTO TEACHER (TNO, TNAME, TSEX, TBIRTHDAY, PROF, DEPART)
+VALUES (804, '李诚', '男', '1958-12-02', '副教授', '计算机系');
+INSERT INTO TEACHER (TNO, TNAME, TSEX, TBIRTHDAY, PROF, DEPART)
+VALUES (856, '张旭', '男', '1969-03-12', '讲师', '电子工程系');
+INSERT INTO TEACHER (TNO, TNAME, TSEX, TBIRTHDAY, PROF, DEPART)
+VALUES (825, '王萍', '女', '1972-05-05', '助教', '计算机系');
+INSERT INTO TEACHER (TNO, TNAME, TSEX, TBIRTHDAY, PROF, DEPART)
+VALUES (831, '刘冰', '女', '1977-08-14', '助教', '电子工程系');
+
+-- 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 TEACHER1;
+
+-- 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、Cname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'
+);
+
+set @@global.sql_mode = 'STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';
+set sql_mode = 'STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';
+
+-- 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记录
+select *
+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。
+-- 同19
+
+-- 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 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');
+
+
+