mysql 高級表查詢示例

Navicat使用

下載地址:https://pan.baidu.com/s/1bpo5mqj

掌握：
#1. 測試+連接數據庫
#2. 新建庫
#3. 新建表，新增字段+類型+約束
#4. 設計表：外鍵
#5. 新建查詢
#6. 創建表模型

#注意：
批量加註釋：ctrl+？鍵
批量去註釋：ctrl+shift+？鍵

練習題

導出的sql語句代碼

/*
數據導入：
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', '體育', '3'), ('4', '美術', '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', '鋼蛋'), ('3', '男', '1', '張三'), ('4', '男', '1', '張一'), ('5', '女', '1', '張二'), ('6', '男', '1', '張四'), ('7', '女', '2', '鐵錘'), ('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', '劉三'), ('14', '男', '3', '劉一'), ('15', '女', '3', '劉二'), ('16', '男', '3', '劉四');
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', '張磊老師'), ('2', '李平老師'), ('3', '劉海燕老師'), ('4', '朱雲海老師'), ('5', '李傑老師');
COMMIT;

SET FOREIGN_KEY_CHECKS = 1;

拷貝上述代碼，新建一個.sql文件，保存到桌面

打開navicat新建數據庫day41，選中新建的數據庫鼠標右鍵選擇運行SQL文件

彈出文件框，選中剛剛保存到桌面的.sql文件便可

快速建表

#準備表、記錄  >>> 命令行
mysql> create database db1;
mysql> use db1;
mysql> source /root/init.sql

# navicat建表

練習題

一、查詢全部的課程的名稱以及對應的任課老師姓名
四、查詢平均成績大於八十分的同窗的姓名和平均成績
七、 查詢沒有報李平老師課的學生姓名
八、 查詢沒有同時選修物理課程和體育課程的學生姓名
九、 查詢掛科超過兩門(包括兩門)的學生姓名和班級
# 參考答案
#一、查詢全部的課程的名稱以及對應的任課老師姓名
SELECT
course.cname,
teacher.tname
FROM
course
INNER JOIN teacher ON course.teacher_id = teacher.tid;
#四、查詢平均成績大於八十分的同窗的姓名和平均成績
SELECT
student.sname,
t1.avg_num
FROM
student
INNER JOIN (
SELECT
  student_id,
  avg(num) AS avg_num
FROM
  score
GROUP BY
  student_id
HAVING
  avg(num) > 80
) AS t1 ON student.sid = t1.student_id;
#七、 查詢沒有報李平老師課的學生姓名(找出報名李平老師課程的學生，而後取反就能夠)
SELECT
student.sname
FROM
student
WHERE
sid NOT IN (
  SELECT DISTINCT
      student_id
  FROM
      score
  WHERE
      course_id IN (
          SELECT
              course.cid
          FROM
              course
          INNER JOIN teacher ON course.teacher_id = teacher.tid
          WHERE
              teacher.tname = '李平老師'
      )
);
#八、 查詢沒有同時選修物理課程和體育課程的學生姓名(沒有同時選修指的是選修了一門的，思路是獲得物理+體育課程的學生信息表，而後基於學生分組，統計count(課程)=1)
SELECT
student.sname
FROM
student
WHERE
sid IN (
  SELECT
      student_id
  FROM
      score
  WHERE
      course_id IN (
          SELECT
              cid
          FROM
              course
          WHERE
              cname = '物理'
          OR cname = '體育'
      )
  GROUP BY
      student_id
  HAVING
      COUNT(course_id) = 1
);

# 九、 查詢掛科超過兩門(包括兩門)的學生姓名和班級
select student.sname,class.caption from class INNER JOIN student
  on class.cid = student.class_id
  WHERE student.sid in 
  (select student_id from score where num < 60
  GROUP BY student_id
  HAVING COUNT(course_id) >=2)
  ;