關于學生資訊和學生成績的查詢(sql陳述句練習)
創建學生資訊表
CREATE TABLE student (
id INT(10) NOT NULL UNIQUE PRIMARY KEY ,
name VARCHAR(20) NOT NULL ,
sex VARCHAR(4) ,
birth YEAR,
department VARCHAR(20) ,
address VARCHAR(50)
);
添加學生資訊
INSERT INTO student VALUES( 901,'張老大', '男',1985,'計算機系', '北京市海淀區');
INSERT INTO student VALUES( 902,'張老二', '男',1986,'中文系', '北京市昌平區');
INSERT INTO student VALUES( 903,'張三', '女',1990,'中文系', '湖南省永州市');
INSERT INTO student VALUES( 904,'李四', '男',1990,'英語系', '遼寧省阜新市');
INSERT INTO student VALUES( 905,'王五', '女',1991,'英語系', '福建省廈門市');
INSERT INTO student VALUES( 906,'王六', '男',1988,'計算機系', '湖南省衡陽市');
創建考試成績表
CREATE TABLE score (
id INT(10) NOT NULL UNIQUE PRIMARY KEY AUTO_INCREMENT ,
stu_id INT(10) NOT NULL ,
c_name VARCHAR(20) ,
grade INT(10)
);
添加考試成績資訊
INSERT INTO score VALUES(NULL,901, '計算機',98);
INSERT INTO score VALUES(NULL,901, '英語', 80);
INSERT INTO score VALUES(NULL,902, '計算機',65);
INSERT INTO score VALUES(NULL,902, '中文',88);
INSERT INTO score VALUES(NULL,903, '中文',95);
INSERT INTO score VALUES(NULL,904, '計算機',70);
INSERT INTO score VALUES(NULL,904, '英語',92);
INSERT INTO score VALUES(NULL,905, '英語',94);
INSERT INTO score VALUES(NULL,906, '計算機',90);
INSERT INTO score VALUES(NULL,906, '英語',85);
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查詢的內容和sql實作
1.查詢student表的所有記錄
SELECT * FROM student
2.查詢student表的第2條到4條記錄
SELECT * FROM student LIMIT 1,2
3.從student表查詢所有學生的學號（id）、姓名（name）和院系（department）的資訊
SELECT id,name, department FROM student
4.從student表中查詢計算機系和英語系的學生的資訊
SELECT * FROM student WHERE department='計算機系' or department='英語系'
5.從student表中查詢每個院系有多少人
SELECT department,count(*) FROM student GROUP BY department
6.從score表中查詢每個科目的最高分
SELECT c_name,grade FROM score GROUP BY c_name ORDER BY grade
7.查詢李四的考試科目（c_name）和考試成績（grade）
select C_name,grade from student left join score on student.id=score.Stu_id where name='李四';
8.查詢所有學生的資訊和考試資訊
SELECT student.id,name,sex,birth,department,address,c_name,grade FROM student,score WHERE student.id=score.stu_id;
9.計算每個學生的總成績
SELECT stu_id,name,SUM(grade)FROM student,score WHERE student.id = score.stu_id GROUP BY stu_id ORDER BY SUM(grade)
10.計算每個考試科目的平均成績
SELECT c_name,AVG(grade) FROM score GROUP BY c_name
11.查詢計算機成績低于95的學生資訊
SELECT * FROM student where id IN (SELECT stu_id FROM score WHERE ((c_name='計算機')AND (grade<95)))
12.查詢同時參加計算機和英語考試的學生的資訊
SELECT * FROM student WHERE id IN(SELECT stu_id FROM score WHERE stu_id IN(
SELECT stu_id FROM score WHERE c_name='英語')AND c_name='計算機')
SELECT * FROM student WHERE id =ANY(SELECT stu_id FROM score WHERE Stu_id IN(
SELECT stu_id FROM score WHERE c_name='計算機')AND c_name='英語');
13.將計算機考試成績按從高到低進行排序
SELECT grade FROM score WHERE c_name='計算機' ORDER BY grade DESC
14.查詢姓張或者姓王的同學的姓名、院系和考試科目及成績
SELECT name,department,c_name,grade FROM student,score WHERE student.id=score.stu_id AND name LIKE '張%' OR name LIKE '王%'
15.查詢都是湖南的學生的姓名、年齡、院系和考試科目及成績
SELECT name,birth,department,c_name,grade FROM student,score WHERE student.id=score.stu_id AND address LIKE '湖南省%'
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