www.cnblogs.com/wupeiqi/p/5748496.html

/*

# 表结构和数据

Navicat Premium Data Transfer

Source Server : localhost

Source Server Type : MySQL

Source Server Version : 50624

Source Host : localhost

Source Database : sqlexam

Target Server Type : MySQL

Target Server Version : 50624

File Encoding : utf-8

Date: 10/21/2016 06:46:46 AM

*/

SET NAMES utf8;

SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------

-- Table structure for `class`

-- ----------------------------

DROP TABLE IF EXISTS `class`;

CREATE TABLE `class` (

`cid` int(11) NOT NULL AUTO_INCREMENT,

`caption` varchar(32) NOT NULL,

PRIMARY KEY (`cid`)

) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

-- ----------------------------

-- Records of `class`

-- ----------------------------

BEGIN;

INSERT INTO `class` VALUES ('1', '三年二班'), ('2', '三年三班'), ('3', '一年二班'), ('4', '二年九班');

COMMIT;

-- ----------------------------

-- Table structure for `course`

-- ----------------------------

DROP TABLE IF EXISTS `course`;

CREATE TABLE `course` (

`cid` int(11) NOT NULL AUTO_INCREMENT,

`cname` varchar(32) NOT NULL,

`teacher_id` int(11) NOT NULL,

PRIMARY KEY (`cid`),

KEY `fk_course_teacher` (`teacher_id`),

CONSTRAINT `fk_course_teacher` FOREIGN KEY (`teacher_id`) REFERENCES `teacher` (`tid`)

) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

-- ----------------------------

-- Records of `course`

-- ----------------------------

BEGIN;

INSERT INTO `course` VALUES ('1', '生物', '1'), ('2', '物理', '2'), ('3', '体育', '3'), ('4', '美术', '2');

COMMIT;

-- ----------------------------

-- Table structure for `score`

-- ----------------------------

DROP TABLE IF EXISTS `score`;

CREATE TABLE `score` (

`sid` int(11) NOT NULL AUTO_INCREMENT,

`student_id` int(11) NOT NULL,

`course_id` int(11) NOT NULL,

`num` int(11) NOT NULL,

PRIMARY KEY (`sid`),

KEY `fk_score_student` (`student_id`),

KEY `fk_score_course` (`course_id`),

CONSTRAINT `fk_score_course` FOREIGN KEY (`course_id`) REFERENCES `course` (`cid`),

CONSTRAINT `fk_score_student` FOREIGN KEY (`student_id`) REFERENCES `student` (`sid`)

) ENGINE=InnoDB AUTO_INCREMENT=53 DEFAULT CHARSET=utf8;

-- ----------------------------

-- Records of `score`

-- ----------------------------

BEGIN;

INSERT INTO `score` VALUES ('1', '1', '1', '10'), ('2', '1', '2', '9'), ('5', '1', '4', '66'), ('6', '2', '1', '8'), ('8', '2', '3', '68'), ('9', '2', '4', '99'), ('10', '3', '1', '77'), ('11', '3', '2', '66'), ('12', '3', '3', '87'), ('13', '3', '4', '99'), ('14', '4', '1', '79'), ('15', '4', '2', '11'), ('16', '4', '3', '67'), ('17', '4', '4', '100'), ('18', '5', '1', '79'), ('19', '5', '2', '11'), ('20', '5', '3', '67'), ('21', '5', '4', '100'), ('22', '6', '1', '9'), ('23', '6', '2', '100'), ('24', '6', '3', '67'), ('25', '6', '4', '100'), ('26', '7', '1', '9'), ('27', '7', '2', '100'), ('28', '7', '3', '67'), ('29', '7', '4', '88'), ('30', '8', '1', '9'), ('31', '8', '2', '100'), ('32', '8', '3', '67'), ('33', '8', '4', '88'), ('34', '9', '1', '91'), ('35', '9', '2', '88'), ('36', '9', '3', '67'), ('37', '9', '4', '22'), ('38', '10', '1', '90'), ('39', '10', '2', '77'), ('40', '10', '3', '43'), ('41', '10', '4', '87'), ('42', '11', '1', '90'), ('43', '11', '2', '77'), ('44', '11', '3', '43'), ('45', '11', '4', '87'), ('46', '12', '1', '90'), ('47', '12', '2', '77'), ('48', '12', '3', '43'), ('49', '12', '4', '87'), ('52', '13', '3', '87');

COMMIT;

-- ----------------------------

-- Table structure for `student`

-- ----------------------------

DROP TABLE IF EXISTS `student`;

CREATE TABLE `student` (

`sid` int(11) NOT NULL AUTO_INCREMENT,

`gender` char(1) NOT NULL,

`class_id` int(11) NOT NULL,

`sname` varchar(32) NOT NULL,

PRIMARY KEY (`sid`),

KEY `fk_class` (`class_id`),

CONSTRAINT `fk_class` FOREIGN KEY (`class_id`) REFERENCES `class` (`cid`)

) ENGINE=InnoDB AUTO_INCREMENT=17 DEFAULT CHARSET=utf8;

-- ----------------------------

-- Records of `student`

-- ----------------------------

BEGIN;

INSERT INTO `student` VALUES ('1', '男', '1', '理解'), ('2', '女', '1', '钢蛋'), ('3', '男', '1', '张三'), ('4', '男', '1', '张一'), ('5', '女', '1', '张二'), ('6', '男', '1', '张四'), ('7', '女', '2', '铁锤'), ('8', '男', '2', '李三'), ('9', '男', '2', '李一'), ('10', '女', '2', '李二'), ('11', '男', '2', '李四'), ('12', '女', '3', '如花'), ('13', '男', '3', '刘三'), ('14', '男', '3', '刘一'), ('15', '女', '3', '刘二'), ('16', '男', '3', '刘四');

COMMIT;

-- ----------------------------

-- Table structure for `teacher`

-- ----------------------------

DROP TABLE IF EXISTS `teacher`;

CREATE TABLE `teacher` (

`tid` int(11) NOT NULL AUTO_INCREMENT,

`tname` varchar(32) NOT NULL,

PRIMARY KEY (`tid`)

) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

-- ----------------------------

-- Records of `teacher`

-- ----------------------------

BEGIN;

INSERT INTO `teacher` VALUES ('1', '张磊老师'), ('2', '李平老师'), ('3', '刘海燕老师'), ('4', '朱云海老师'), ('5', '李杰老师');

COMMIT;

SET FOREIGN_KEY_CHECKS = 1;

----------------------------------------------------------------------------------------------------------------------------------------

# mysql 练习题答案

select * from score where num > 60;

select * from course;

select teacher_id, count(cname) from course group by teacher_id;

select * from course left join teacher on course.teacher_id = teacher.id;

select * from student left join class on student.class_id = class.id;

select gender, count(sid) from student GROUP BY gender;

# 临时表

select num, course_id from (select num, course_id from score where num > 60 ) as B;