文件名称：mysql常用查询测试及答案
文件大小：2KB
文件格式：RAR
更新时间：2018-05-09 10:49:26
mysql in any jion
mysql常用查询测试及答案: 参考链接： http://blog.sina.com.cn/s/blog_767d65530101861c.html -------------------创建如下表---------------------- 1.创建表 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) ); 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) ); 2.为student表和score表增加记录向student表插入记录的INSERT 语句如下： INSERT INTO student VALUES( 901,'张老大', '男',1985,'计算机系', '北京市海淀区'); INSERT INTO student VALUES( 902,'张老二', '男',1986,'中文系', '北京市昌平区'); INSERT INTO student VALUES( 903,'张三', '女',1990,'中文系', '湖南省永州市'); INSERT INTO student VALUES( 904,'李四', '男',1990,'英语系', '辽宁省阜新市'); INSERT INTO student VALUES( 905,'王五', '女',1991,'英语系', '福建省厦门市'); INSERT INTO student VALUES( 906,'王六', '男',1988,'计算机系', '湖南省衡阳市'); 向score表插入记录的INSERT语句如下： INSERT INTO score VALUES(NULL,901, '计算机',98); INSERT INTO score VALUES(NULL,901, '英语', 80); INSERT INTO score VALUES(NULL,902, '计算机',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, '计算机',70); INSERT INTO score VALUES(NULL,904, '英语',92); INSERT INTO score VALUES(NULL,905, '英语',94); INSERT INTO score VALUES(NULL,906, '计算机',90); INSERT INTO score VALUES(NULL,906, '英语',85); --------练习及答案---------- -- 3.查询student表的所有记录 -- SELECT * FROM student -- 4.查询student表的第2条到4条记录 -- SELECT * from student LIMIT 1,4 -- 5.从student表查询所有学生的学号（id）、姓名（name）和院系（department）的信息 -- SELECT s.id,s.name,s.department FROM student s -- 6.从student表中查询计算机系和英语系的学生的信息 -- SELECT * FROM student s WHERE s.department in ('英语系','计算机系') -- 7.从student表中查询年龄18~22岁的学生信息 -- SELECT *,2015-s.birth AS age FROM student s WHERE 2015-s.birth BETWEEN 20 and 25; -- SELECT *,2015-birth AS age FROM student s WHERE 2015-birth>=18 AND 2015-birth<=2 -- 8.从student表中查询每个院系有多少人 -- SELECT department, COUNT(1) FROM student s GROUP BY department; -- SELECT department, COUNT(id) FROM student s GROUP BY department; -- SELECT department, COUNT(*) FROM student s GROUP BY department; -- 9.从score表中查询每个科目的最高分 -- SELECT sc.c_name,MAX(sc.grade) scores FROM score sc GROUP BY sc.c_name -- 10.查询李四的考试科目（c_name）和考试成绩（grade） -- SELECT s.`name`,sc.c_name,sc.grade FROM student s,score sc WHERE s.id=sc.stu_id and s.`name`='李四'; -- SELECT c_name, grade FROM score WHERE stu_id=(SELECT id FROM student WHERE name= '李四' ); -- SELECT sc.c_name,sc.grade,s.`name` FROM score sc INNER JOIN student s ON sc.stu_id=s.id and s.`name`='李四'; -- 默认为inner JOIN -- 11.用连接的方式查询所有学生的信息和考试信息 -- SELECT * FROM score sc INNER JOIN student s ON sc.stu_id=s.id; -- SELECT * FROM score sc LEFT JOIN student s ON sc.stu_id=s.id; -- 12.计算每个学生的总成绩 -- SELECT s.`name`,s.id, SUM(sc.grade) FROM student s,score sc WHERE s.id=sc.stu_id GROUP BY s.id; -- SELECT student.id,name,SUM(grade) FROM student,score WHERE student.id=score.stu_id GROUP BY id; -- 13.计算每个考试科目的平均成绩 -- SELECT sc.c_name ,AVG(sc.grade) as avg_grade FROM score sc GROUP BY sc.c_name; -- SELECT c_name,AVG(grade) FROM score GROUP BY c_name; -- 14.查询计算机成绩低于95的学生信息 -- SELECT s.address,s.birth,s.department,s.id,s.`name`,s.sex,sc.grade FROM student s, score sc WHERE s.department='计算机系' and sc.grade<95 GROUP BY s.id; -- SELECT * from student s WHERE s.department='计算机系' AND s.id in (SELECT sc.id FROM score sc WHERE sc.grade<95); -- 15.查询同时参加计算机和英语考试的学生的信息 -- SELECT * FROM student st WHERE id=ANY ( SELECT sc1.stu_id FROM score sc1 WHERE sc1.stu_id IN(SELECT sc.stu_id from score sc WHERE sc.c_name='计算机') and sc1.c_name='英语'); -- SELECT * FROM student st WHERE id in ( SELECT sc1.stu_id FROM score sc1 WHERE sc1.stu_id IN(SELECT sc.stu_id from score sc WHERE sc.c_name='计算机') and sc1.c_name='英语'); -- SELECT * FROM student st WHERE id = ANY (SELECT stu_id FROM score WHERE stu_id IN (SELECT stu_id FROM score WHERE c_name = '英语') AND c_name = '计算机'); -- SELECT a.* FROM student a ,score b ,score c WHERE a.id=b.stu_id AND b.c_name='计算机' AND a.id=c.stu_id AND c.c_name='英语'; -- SELECT st.* FROM student st,score sc1,score sc2 WHERE st.id = sc1.stu_id AND sc1.c_name='计算机' and st.id = sc2.stu_id AND sc2.c_name='英语' -- 16.将计算机考试成绩按从高到低进行排序 -- SELECT * FROM score sc WHERE sc.c_name='计算机' ORDER BY sc.grade DESC -- 17.从student表和score表中查询出学生的学号，然后合并查询结果//(nunin会自动排重) -- SELECT st.id FROM student st UNION SELECT sc.stu_id FROM score sc -- 18.查询姓张或者姓王的同学的姓名、院系和考试科目及成绩 -- SELECT st.`name`,st.department,sc.c_name,sc.grade FROM student st,score sc WHERE st.id = sc.stu_id AND (st.`name` LIKE '张%' OR st.`name` LIKE '王%'); -- SELECT student.id, name,sex,birth,department, address, c_name,grade FROM student, score WHERE (name LIKE '张%' OR name LIKE '王%') AND student.id=score.stu_id ; -- 19.查询都是湖南的学生的姓名、年龄、院系和考试科目及成绩 -- SELECT st.`name`, (select year(NOW())) - st.birth as age,st.department,sc.c_name,sc.grade,st.address FROM student st,score sc WHERE st.id=sc.stu_id and st.address LIKE '%湖南%'
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sql查询练习.txt