周測mysql

3.查詢student表的所有記錄

SELECT * FROM student;

4.查詢student表的第2條到4條selec記錄

SELECT * FROM student LIMIT 1,3;

5.從student表查詢所有學生的學號（id）、姓名（name）和院系（department）的信息

SELECT id,name,department FROM student;

6.從student表中查詢slex計算機系和英語系的學生的信息

SELECT * FROM student WHERE department IN ('計算機系','英語系');

7.從student表中查詢年齡18~22歲的學生信息

SELECT id,name,sex,2013-birth AS age,department,address FROM student WHERE 2018-birth BETWEEN  18 AND 22;

8.從student表中查詢每個院系有多少人

SELECT department, COUNT(id) FROM student GROUP BY department;

9.從score表中查詢每個科目的最高分

SELECT c_name,MAX(grade) FROM score GROUP BY c_name;

10.查詢李四的考試科目（c_name）和考試成績（grade）

SELECT c_name, grade FROM score WHERE stu_id= (SELECT id FROM student  WHERE name= '李四' );

11.用連接的方式查詢所有學生的信息和考試信息

SELECTstudent.id,name,sex,birth,department,address,c_name,grade FROM student,score WHERE student.id=score.stu_id;

12.計算每個學生的總成績

 SELECT student.id,name,SUM(grade) FROM student,score WHERE student.id=score.stu_id GROUP BY id;

13.計算每個考試科目的平均成績

 SELECT c_name,AVG(grade) FROM score GROUP BYc_name;

14.查詢計算機成績低於95的學生信息

 SELECT * FROM student WHERE id IN (SELECT stu_id FROM score WHEREc_name="計算機" and grade<95);

15.查詢同時參加計算機和英語考試的學生的信息

 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' );

 SELECT a.* FROM student a ,score b ,score c WHEREa.id=b.stu_id ANDb.c_name='計算機' ANDa.id=c.stu_id ANDc.c_name='英語';

16.將計算機考試成績按從高到低進行排序

 SELECT stu_id, grade  FROM score WHERE c_name= '計算機'  ORDER BY grade DESC;

17.從student表和score表中查詢出學生的學號，然後合併查詢結果

 SELECT id FROM student UNION SELECTstu_id  FROM score;

18.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 student.id, name,sex,birth,department,address, c_name,grade FROMstudent, score WHERE  (name LIKE '張%'  OR name LIKE  '王%')  AND  student.id=score.stu_id ;

19.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 student.id, name,sex,birth,department,address, c_name,grade FROMstudent, score WHEREaddress LIKE '湖南%'   AND  student.id=score.stu_id;