SQL語句練習(xí)（經(jīng)典sql語句）

1山橄、查詢"01"課程比"02"課程成績高的學(xué)生的信息及課程分?jǐn)?shù)

select s.s_id, s.s_name, s.s_birth, s.s_sex, c.s_id, c.c_id, c.s_score 01score ,c1.s_score 02score from Student s inner join Score c on s.s_id = c.s_id and c.c_id = '01' left join score c1 on s.s_id = c1.s_id and c1.c_id = '02' where c.s_score > c1.s_score;

或者

select s1.*, s2.01_score, s2.02_score from student s1,(select t1.s_id as s_id, t1.s_score as 01_score,t2.s_score as 02_score from score t1,score t2 where t1.s_id = t2.s_idand t1.c_id = '01' and t2.c_id = '02' and t1.s_score > t2.s_score ) s2 where s1.s_id = s2.s_id;

2悦即、查詢"01"課程比"02"課程成績低的學(xué)生的信息及課程分?jǐn)?shù)

select s.s_id, s.s_name, s.s_birth, s.s_sex, c.s_id, c.c_id, c.s_score 01score ,c1.s_score 02score from Student s inner join Score c on s.s_id = c.s_id and c.c_id = '01' left join score c1 on s.s_id = c1.s_id and c1.c_id = '02' where c.s_score < c1.s_score;

3皂甘、查詢平均成績大于等于60分的同學(xué)的學(xué)生編號和學(xué)生姓名和平均成績

select s.s_name, s.s_id, avg(c.s_score) cvg from student s inner join score c on s.s_id = c.s_id group by s.s_id having cvg > 60;

4雏婶、查詢平均成績小于60分的同學(xué)的學(xué)生編號和學(xué)生姓名和平均成績 (包括有成績的和無成績的)

select s.s_name, s.s_id, avg(c.s_score) cvg from student s inner join score c on s.s_id = c.s_id group by s.s_id having cvg < 60 union select s.s_name, s.s_id, avg(c.s_score) cvg from student s left join score c on s.s_id = c.s_id group by s.s_id having cvg is null;

5辕翰、查詢所有同學(xué)的學(xué)生編號培遵、學(xué)生姓名浪藻、選課總數(shù)捐迫、所有課程的總成績

select s.s_id,s.s_name name, sum(c.s_score) sum, count(1) count from student s left join score c on s.s_id = c.s_id group by s.s_id;

6、查詢"李"姓老師的數(shù)量?

select substring(t_name,1,1) as name , count(1) as count from teacher where t_name like '李%' group by name;

7爱葵、查詢學(xué)過"張三"老師授課的同學(xué)的信息?

select t.t_name tname, st.s_name stname, sc.s_score scscore from teacher t left join ?Course cou on t.t_id = cou.t_id left join score sc on cou.c_id = sc.c_id left join student st on sc.s_id = st.s_id where t.t_name = '張三';

8施戴、查詢沒學(xué)過"張三"老師授課的同學(xué)的信息 (吳蘭，王菊)

1.哪些學(xué)生學(xué)習(xí) ‘張三’老師的課程 (s_id)

select st.s_id sid from teacher t left join Course cou on t.t_id = cou.t_id left join score sc on cou.c_id = sc.c_id left join student st on sc.s_id = st.s_id where t.t_name = '張三';

2.通過查詢學(xué)生表钧惧，通過where使用not int 進(jìn)行過濾 ?

select * from student where student.s_id not in (select st.s_id sid from teacher t left join Course cou on t.t_id = cou.t_id left join score sc on cou.c_id = sc.c_id left join student st on sc.s_id = st.s_id where t.t_name = '張三');

9暇韧、查詢學(xué)過編號為"01"并且也學(xué)過編號為"02"的課程的同學(xué)的信息?

1.查詢出課程編號為02的學(xué)生 sid

select * from student st inner join score sc on st.s_id = sc.s_id and sc.c_id = 02;

2.查詢出課程編碼為01的學(xué)生，通過where sid in () 進(jìn)行過濾 ?

select * from student st1 inner join score sc1 on st1.s_id = sc1.s_id and sc1.c_id = 01 where st1.s_id in (select sc.s_id from student st inner join score sc on st.s_id = sc.s_id and sc.c_id = 02)?

10浓瞪、查詢學(xué)過編號為"01"但是沒有學(xué)過編號為"02"的課程的同學(xué)的信息

select * from student st1 left join score sc1 on st1.s_id = sc1.s_id and sc1.c_id = 01 where st1.s_id not in (select sc.s_id from student st left join score sc on st.s_id = sc.s_id and sc.c_id = 02);

11懈玻、查詢沒有學(xué)全所有課程的同學(xué)的信息

1.三張分?jǐn)?shù)表連接，查詢學(xué)習(xí)過所有課程的學(xué)生

select st2.s_id from student st2 inner join score sc2 on st2.s_id = sc2.s_id and sc2.c_id = 03 where st2.s_id in (select sc1.s_id from student st1 inner join score sc1 on st1.s_id = sc1.s_id and sc1.c_id = 01 where st1.s_id in (select sc.s_id from student st inner join score sc on st.s_id = sc.s_id and sc.c_id = 02))

2.通過not in 進(jìn)行過濾 ?

select * from student where student.s_id not in (select st2.s_id from student st2 inner join score sc2 on st2.s_id = sc2.s_id and sc2.c_id = 03 where st2.s_id in (select sc1.s_id from student st1 inner join score sc1 on st1.s_id = sc1.s_id and sc1.c_id = 01 where st1.s_id in (select sc.s_id from student st inner join score sc on st.s_id = sc.s_id and sc.c_id = 02)));?

12 乾颁、查詢至少有一門課與學(xué)號為"01"的同學(xué)所學(xué)相同的同學(xué)的信息

1.查詢出01同學(xué)的課程信息 (c_id) ?

select sc.c_id from score sc inner join student st on sc.s_id = st.s_id where st.s_id = '01'

2.查詢所有學(xué)生c_id2 ?

select distinct st1.s_name from student st1 left join score sc1 on st1.s_id = sc1.s_id?

3.c_id2 in (c_id) , 有同學(xué)報(bào)名多門課程涂乌，可以使用distinct過濾

select distinct st1.s_name from student st1 left join score sc1 on st1.s_id = sc1.s_id where sc1.c_id in (select sc.c_id from score sc inner join student st on sc.s_id = st.s_id where st.s_id = '01');

13、查詢和"01"號的同學(xué)學(xué)習(xí)的課程完全相同的其他同學(xué)的信息?

1. 01學(xué)生學(xué)習(xí)的課程id (c_id)英岭，我們把c_id給拼接(concat)到一起 ?

select group_concat(sc.c_id) from student st inner join score sc on st.s_id = sc.s_id and st.s_id = '01';?

查詢其他學(xué)生的信息湾盒，也使用concat拼接到一起，或者使用 in ??

select st.s_name,group_concat(sc.c_id) cc from student st inner join score sc on st.s_id = sc.s_id group by st.s_id having cc in (select group_concat(sc.c_id) from student st inner join score sc on st.s_id = sc.s_id and st.s_id = '01');

14诅妹、查詢沒學(xué)過"張三"老師講授的任一門課程的學(xué)生姓名

1.查詢出張三講授的課程罚勾，通過課程查詢到學(xué)生的s_id ?

select sc.s_id from score sc inner join Course cu on sc.c_id = cu.c_id inner join teacher tc on cu.t_id = tc.t_id where tc.t_name = '張三';

2.not in 進(jìn)行過濾 ?

select * from student where student.s_id not in (select sc.s_id from score sc inner join Course cu on sc.c_id = cu.c_id inner join teacher tc on cu.t_id = tc.t_id where tc.t_name = '張三');

15、查詢兩門及其以上不及格課程的同學(xué)的學(xué)號吭狡，姓名及其平均成績?

?1.where 分?jǐn)?shù) < 60 , 通過 group by(s_id) 進(jìn)行分組尖殃，通過count函數(shù)進(jìn)行過濾

// 60分一下的不加入統(tǒng)計(jì)?

select st.s_name, st.s_id, avg(sc.s_score) avg where sc1.s_id = st.s_id as avg from student st left join score sc on st.s_id = sc.s_id where sc.s_score < 60 group by st.s_id having count(1) >= 2?

// 60分以上的也加入統(tǒng)計(jì) ?

select st.s_name, st.s_id, (select avg(sc1.s_score) from student st1 left join score sc1 on st1.s_id = sc1.s_id) avg where sc1.s_id = st.s_id as avg from student st left join score sc on st.s_id = sc.s_id where sc.s_score < 60 group by st.s_id having count(1) >= 2?

?2, 某個(gè)同學(xué)的平均分 ?

select avg(sc1.s_score) from student st1 left join score sc1 on st1.s_id = sc1.s_id where sc1.s_id = '01';?

16 、檢索"01"課程分?jǐn)?shù)小于60划煮，按分?jǐn)?shù)降序排列的學(xué)生信息

select st.s_name, sc.c_id, sc.s_score from student st inner join score sc on st.s_id = sc.s_id and sc.c_id = '01' and sc.s_score < 60 order by sc.s_score desc;

--表信息

--學(xué)生表

CREATE TABLE `Student`(

`s_id` VARCHAR(20),

`s_name` VARCHAR(20) NOT NULL DEFAULT '',

`s_birth` VARCHAR(20) NOT NULL DEFAULT '',

`s_sex` VARCHAR(10) NOT NULL DEFAULT '',

PRIMARY KEY(`s_id`)

);

--課程表

CREATE TABLE `Course`(

`c_id`? VARCHAR(20),

`c_name` VARCHAR(20) NOT NULL DEFAULT '',

`t_id` VARCHAR(20) NOT NULL,

PRIMARY KEY(`c_id`)

);

--教師表

CREATE TABLE `Teacher`(

`t_id` VARCHAR(20),

`t_name` VARCHAR(20) NOT NULL DEFAULT '',

PRIMARY KEY(`t_id`)

);

--成績表

CREATE TABLE `Score`(

`s_id` VARCHAR(20),

`c_id`? VARCHAR(20),

`s_score` INT(3),

PRIMARY KEY(`s_id`,`c_id`)

);

--插入學(xué)生表測試數(shù)據(jù)

insert into Student values('01' , '趙雷' , '1990-01-01' , '男');

insert into Student values('02' , '錢電' , '1990-12-21' , '男');

insert into Student values('03' , '孫風(fēng)' , '1990-05-20' , '男');

insert into Student values('04' , '李云' , '1990-08-06' , '男');

insert into Student values('05' , '周梅' , '1991-12-01' , '女');

insert into Student values('06' , '吳蘭' , '1992-03-01' , '女');

insert into Student values('07' , '鄭竹' , '1989-07-01' , '女');

insert into Student values('08' , '王菊' , '1990-01-20' , '女');

--課程表測試數(shù)據(jù)

insert into Course values('01' , '語文' , '02');

insert into Course values('02' , '數(shù)學(xué)' , '01');

insert into Course values('03' , '英語' , '03');

--教師表測試數(shù)據(jù)

insert into Teacher values('01' , '張三');

insert into Teacher values('02' , '李四');

insert into Teacher values('03' , '王五');

--成績表測試數(shù)據(jù)

insert into Score values('01' , '01' , 80);

insert into Score values('01' , '02' , 90);

insert into Score values('01' , '03' , 99);

insert into Score values('02' , '01' , 70);

insert into Score values('02' , '02' , 60);

insert into Score values('02' , '03' , 80);

insert into Score values('03' , '01' , 80);

insert into Score values('03' , '02' , 80);

insert into Score values('03' , '03' , 80);

insert into Score values('04' , '01' , 50);

insert into Score values('04' , '02' , 30);

insert into Score values('04' , '03' , 20);

insert into Score values('05' , '01' , 76);

insert into Score values('05' , '02' , 87);

insert into Score values('06' , '01' , 31);

insert into Score values('06' , '03' , 34);

insert into Score values('07' , '02' , 89);

insert into Score values('07' , '03' , 98);

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