Tasks.sql

--------------------------------Task01------------------------------------
-- 创建数据库

CREATE DATABASE shop;


-- 选择使用数据库

use shop;

-- 创建数据库示例，使用编码
CREATE DATABASE dbname DEFAULT CHARSET utf8 COLLATE utf8_general_ci;
CREATE TABLE `author` (
    `authorid` char(20) NOT NULL,
    `name` char(20) NOT NULL,
    `age` char(20) NOT NULL,
    `country` char(20) NOT NULL
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=1;


-- 创建商品表
CREATE TABLE product(
     product_id CHAR(4) NOT NULL,
     product_name VARCHAR(100) NOT NULL,
     product_type VARCHAR(32) NOT NULL,
     sale_price INTEGER,
     purchase_price INTEGER,
     regist_date DATE,
     PRIMARY KEY(product_id)
);

-- 删除表
DROP TABLE product;

-- 修改表结构
ALTER TABLE product ADD COLUMN product_name_pinyin VARCHAR(100);

ALTER TABLE product DROP COLUMN product_name_pinyin;

-- 清空表

TRUNCATE TABLE product;

-- 修改所有的注册时间
UPDATE product
SET regist_date = '2009-10-10';

-- 仅修改部分商品的单价
UPDATE product
SET sale_price = sale_price * 10
WHERE product_type = '厨房用具';

-- 将商品编号为 0008 的数据（圆珠笔）的登记日期更新为 NULL
UPDATE product
SET regist_date = NULL
WHERE product_id = '0008';

-- 合并后的写法
UPDATE product
SET sale_price = sale_price * 10,
    purchase_price = purchase_price / 2
WHERE product_type = '厨房用具';

-- 创建测试表

CREATE TABLE productins(
    product_id     CHAR(4)      NOT NULL,
    product_name   VARCHAR(100) NOT NULL,
    product_type   VARCHAR(32)  NOT NULL,
    sale_price     INTEGER      DEFAULT 0,
    purchase_price INTEGER ,
    regist_date    DATE ,
    PRIMARY KEY (product_id)
);

-- 包含列清单
INSERT INTO productins (
    product_id,
    product_name,
    product_type,
    sale_price,
    purchase_price,
    regist_date)
VALUES (
    '0005',
    '高压锅',
    '厨房用具',
    6800,
    5000,
    '2009-01-15'
);

-- 省略列清单
INSERT INTO productins
VALUES (
    '0005',
    '高压锅',
    '厨房用具',
    6800,
    5000,
    '2009-01-15'
);
-- 通常的 INSERT
INSERT INTO productins
VALUES ('0002', '打孔器', '办公用品', 500, 320, '2009-09-11');

INSERT INTO productins
VALUES ('0003', '运动 T 恤', '衣服', 4000, 2800, NULL);

INSERT INTO productins
VALUES ('0004', '菜刀', '厨房用具', 3000, 2800, '2009-09-20');

-- 多行 INSERT （ DB2、SQL、SQL Server、 PostgreSQL 和 MySQL 多行插入）
INSERT INTO productins
VALUES
('0002', '打孔器', '办公用品', 500, 320, '2009-09-11'),
('0003', '运动 T 恤', '衣服', 4000, 2800, NULL),
('0004', '菜刀', '厨房用具', 3000, 2800, '2009-09-20');


-- 将商品表中的数据复制到商品复制表中
INSERT INTO productcopy (
    product_id,
    product_name,
    product_type,
    sale_price,
    purchase_price,
    regist_date
)
SELECT
    product_id,
    product_name,
    product_type,
    sale_price,
    purchase_price,
    regist_date
FROM Product;

- DML ：插入数据
START TRANSACTION;
INSERT INTO product VALUES('0001', 'T 恤衫', '衣服', 1000, 500, '2009-09-20');
INSERT INTO product VALUES('0002', '打孔器', '办公用品', 500, 320, '2009-09-11');
INSERT INTO product VALUES('0003', '运动 T 恤', '衣服', 4000, 2800, NULL);
INSERT INTO product VALUES('0004', '菜刀', '厨房用具', 3000, 2800, '2009-09-20');
INSERT INTO product VALUES('0005', '高压锅', '厨房用具', 6800, 5000, '2009-01-15');
INSERT INTO product VALUES('0006', '叉子', '厨房用具', 500, NULL, '2009-09-20');
INSERT INTO product VALUES('0007', '擦菜板', '厨房用具', 880, 790, '2008-04-28');
INSERT INTO product VALUES('0008', '圆珠笔', '办公用品', 100, NULL, '2009-11-11');
COMMIT;

-- 主键，自增长属性

CREATE TABLE ai_test(
    ai_id int not null AUTO_INCREMENT,
    ai_unique varchar(20) not null,
    PRIMARY KEY(ai_id),
    CONSTRAINT ai_unique_ui UNIQUE (ai_unique)
)

INSERT INTO ai_test VALUES (0,'124');
INSERT INTO ai_test VALUES (0,'125');
INSERT INTO ai_test VALUES (0,'126');
INSERT INTO ai_test VALUES (0,'127');
INSERT INTO ai_test VALUES (0,'124');
INSERT INTO ai_test VALUES (0,'124');
INSERT INTO ai_test VALUES (0,'124');
INSERT INTO ai_test VALUES (0,'124');
INSERT INTO ai_test VALUES (0,'128');

-- 创建学生表，主键，自增长
CREATE TABLE students_new(
    student_id int not null AUTO_INCREMENT,
    student_name varchar(20) not null,
    student_age int not null,
    student_weight float not null DEFAULT 99.9,
    PRIMARY KEY(student_id)
);
INSERT INTO students_new(student_name,student_age) VALUES('王菲',19);

INSERT INTO students_new(student_id,student_name,student_age,student_weight) VALUES(5,'张玉婷',22,109.99);

INSERT INTO students_new(student_name,student_age) VALUES('丛老师',26);

INSERT INTO students_new VALUES(0,'杨小辉',3,42);

-- 练习 1-创建表
CREATE TABLE Addressbook(
   regist_no        INTEGER          NOT NULL,
   name             VARCHAR(128)     NOT NULL,
   address          VARCHAR(256)     NOT NULL,
   tel_no           CHAR(10)     ,
   mail_address     CHAR(20)     ,
   PRIMARY KEY (regist_no)
);
-- 练习 1-增加列
-- [MySQL]
ALTER TABLE Addressbook ADD COLUMN postal_code CHAR(8) NOT NULL ;

--------------------------------Task02------------------------------------
-- 用来选取 product_type 列为衣服的记录的 SELECT 语句
SELECT product_name, product_type
FROM product
WHERE product_type = '衣服';

-- 也可以选取出不是查询条件的列（条件列与输出列不同）
SELECT product_name
FROM product
WHERE product_type = '衣服';

-- SQL 语句可以使用 AS 关键字为列设定别名（用中文时需要双引号（""））。
SELECT product_id     AS id,
       product_name   AS name,
       purchase_price AS "进货单价"
FROM product;

-- 使用 DISTINCT 剔除 product_type 列中重复的数据
SELECT DISTINCT product_type
FROM product;

-- 选取出 sale_price 列为 500 的记录
SELECT product_name, product_type
FROM product
WHERE sale_price = 500;

-- SQL 语句中也可以使用运算表达式
SELECT
    product_name,
    sale_price,
    sale_price * 2 AS "sale_price x2"
FROM product;

-- WHERE 子句的条件表达式中也可以使用计算表达式
SELECT product_name, sale_price, purchase_price
FROM product
WHERE sale_price-purchase_price >= 500;

-- 选取 NULL 的记录
SELECT product_name,purchase_price
FROM product
WHERE purchase_price IS NULL;

-- 选取不为 NULL 的记录
SELECT product_name,purchase_price
FROM product
WHERE purchase_price IS NOT NULL;

-- 选取出销售单价大于等于 1000 元的记录
SELECT product_name, product_type, sale_price
FROM product
WHERE sale_price >= 1000;

-- 向上面代码清单的查询条件中添加 NOT 运算符
SELECT product_name, product_type, sale_price
FROM product
WHERE NOT sale_price >= 1000;

-- 将查询条件原封不动地写入条件表达式，会得到错误结果
SELECT product_name, product_type, regist_date
FROM product
WHERE product_type = '办公用品'
AND regist_date = '2009-09-11'
OR regist_date = '2009-09-20';

-- 通过使用括号让 OR 运算符先于 AND 运算符执行
SELECT product_name, product_type, regist_date
FROM product
WHERE product_type = '办公用品'
AND ( regist_date = '2009-09-11'
OR regist_date = '2009-09-20');

-- 练习二

SELECT product_name, regist_date
FROM product
WHERE regist_date > '2009-04-28';

SELECT *
FROM product
WHERE purchase_price = NULL;

SELECT *
FROM product
WHERE purchase_price <> NULL;

SELECT *
FROM product
WHERE product_name > NULL;


-- SELECT 语句 1
SELECT product_name, sale_price, purchase_price
FROM product
WHERE sale_price >= purchase_price + 500;

-- SELECT 语句 2
SELECT product_name, sale_price, purchase_price
FROM product
WHERE sale_price - 500 >= purchase_price;

-- 从 product 表中选取出满足“销售单价打九折之后利润高于 100 元的办公用品和厨房用具”条件的记录
SELECT product_name, product_type,
       sale_price * 0.9 - purchase_price AS profit
FROM product
WHERE sale_price * 0.9 - purchase_price > 100
   AND (product_type = '办公用品'
        OR product_type = '厨房用具');


-- 计算全部数据的行数（包含 NULL）
SELECT COUNT(*)
FROM product;

-- 计算 NULL 以外数据的行数
SELECT COUNT(purchase_price)
FROM product;

-- 计算销售单价和进货单价的合计值
SELECT SUM(sale_price), SUM(purchase_price)
FROM product;

-- 计算销售单价和进货单价的平均值
SELECT AVG(sale_price), AVG(purchase_price)
FROM product;

-- MAX 和 MIN 也可用于非数值型数据
SELECT MAX(regist_date), MIN(regist_date)
FROM product;

-- 计算去除重复数据后的数据行数
SELECT COUNT(DISTINCT product_type)
FROM product;

-- 是否使用 DISTINCT 时的动作差异（SUM 函数）
SELECT SUM(sale_price), SUM(DISTINCT sale_price)
FROM product;

-- 按照商品种类统计数据行数
SELECT product_type, COUNT(*)
FROM product
GROUP BY product_type;

-- 不含 GROUP BY
SELECT product_type, COUNT(*)
FROM product;

-- 包含 NULL 值

SELECT purchase_price, COUNT(*)
FROM product
GROUP BY purchase_price;

-- GROUP BY 对筛选出的数据进行处理
SELECT purchase_price, COUNT(*)
FROM product
WHERE product_type = '衣服'
GROUP BY purchase_price;

-- 错误形式（因为 product_name 不包含在 GROUP BY 聚合键中）
SELECT product_type, COUNT(*)
FROM product
GROUP BY product_type
HAVING product_name = '圆珠笔';

-- 降序排列
SELECT product_id, product_name, sale_price, purchase_price
FROM product
ORDER BY sale_price DESC;

-- 多个排序键
SELECT product_id, product_name, sale_price, purchase_price
FROM product
ORDER BY sale_price, product_id;

-- 当用于排序的列名中含有 NULL 时，NULL 会在开头或末尾进行汇总。
SELECT product_id, product_name, sale_price, purchase_price
FROM product
ORDER BY purchase_price;

-- 练习 3 请编写一条 SELECT 语句，求出销售单价（sale_price 列）合计值大于进货单价（purchase_price 列）
-- 合计值 1.5 倍的商品种类。执行结果如下所示。

SELECT product_type, SUM(sale_price),SUM(purchase_price)
FROM product
GROUP BY product_type
HAVING SUM(sale_price) > SUM(purchase_price) * 1.5;


---------------------------Task03-----------------------------------

CREATE VIEW productsum (product_type, cnt_product)
AS
SELECT product_type, COUNT(*)
FROM product
GROUP BY product_type
ORDER BY product_type;

-- 创建商店表

CREATE TABLE shop_product(
  shop_id    CHAR(4)       NOT NULL,
  shop_name  VARCHAR(200)  NOT NULL,
  product_id CHAR(4)       NOT NULL,
  quantity   INTEGER       NOT NULL,
  PRIMARY KEY (shop_id, product_id)
);

INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000A','东京','0001',30);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000A','东京','0002',50);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000A','东京','0003',15);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000B','名古屋','0002',30);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000B','名古屋','0003',120);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000B','名古屋','0004',20);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000B','名古屋','0006',10);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000B','名古屋','0007',40);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000C','大阪','0003',20);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000C','大阪','0004',50);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000C','大阪','0006',90);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000C','大阪','0007',70);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity) VALUES ('000D','福冈','0001',100);

-- 创建视图，来自于 product 表和 shop 表

CREATE VIEW view_shop_product(product_type, sale_price, shop_name)
AS
SELECT product_type, sale_price, shop_name
FROM product,shop_product
WHERE product.product_id = shop_product.product_id;

-- 视图上查询
SELECT sale_price, shop_name
FROM view_shop_product
WHERE product_type = '衣服';

-- 更新视图

UPDATE productsum
SET sale_price = '5000'
WHERE product_type = '办公用品';

-- 删除视图

DROP VIEW productSum;

-- 嵌套子查询

SELECT product_type, cnt_product
FROM (SELECT *
    FROM (
            SELECT product_type, COUNT(*) AS cnt_product
            FROM product
            GROUP BY product_type
          ) AS productsum
    WHERE cnt_product = 4
    ) AS productsum2;

-- 标量子查询
SELECT product_id, product_name, sale_price
FROM product
WHERE sale_price > (
  SELECT AVG(sale_price) FROM product
);

-- 标量子查询

SELECT product_id,
     product_name,
     sale_price,
     (SELECT AVG(sale_price) FROM product) AS avg_price
FROM product;

-- 关联子查询,`选取出各商品种类中高于该商品种类的平均销售单价的商品`
SELECT product_type, product_name, sale_price
FROM product AS p1
WHERE sale_price > (SELECT AVG(sale_price)
                  FROM product AS p2
                  WHERE p1.product_type = p2.product_type
                  GROUP BY product_type);

-- `查询出销售单价高于平均销售单价的商品`

SELECT product_id, product_name, sale_price
FROM product
WHERE sale_price > (SELECT AVG(sale_price) FROM product);

-- 练习 3 -- 创建视图

CREATE VIEW ViewPractice5_1 AS
SELECT product_name, sale_price, regist_date
FROM product
WHERE sale_price >= 1000
AND regist_date = '2009-09-20';

-- 创建表

-- DDL ：创建表
USE shop;
DROP TABLE IF EXISTS samplemath;
CREATE TABLE samplemath(
  m float(10,3),
  n INT,
  p INT
);

-- DML ：插入数据
START TRANSACTION; -- 开始事务
INSERT INTO samplemath(m, n, p) VALUES (500, 0, NULL);
INSERT INTO samplemath(m, n, p) VALUES (-180, 0, NULL);
INSERT INTO samplemath(m, n, p) VALUES (NULL, NULL, NULL);
INSERT INTO samplemath(m, n, p) VALUES (NULL, 7, 3);
INSERT INTO samplemath(m, n, p) VALUES (NULL, 5, 2);
INSERT INTO samplemath(m, n, p) VALUES (NULL, 4, NULL);
INSERT INTO samplemath(m, n, p) VALUES (8, NULL, 3);
INSERT INTO samplemath(m, n, p) VALUES (2.27, 1, NULL);
INSERT INTO samplemath(m, n, p) VALUES (5.555,2, NULL);
INSERT INTO samplemath(m, n, p) VALUES (NULL, 1, NULL);
INSERT INTO samplemath(m, n, p) VALUES (8.76, NULL, NULL);
COMMIT; -- 提交事务

SELECT
m,
ABS(m) AS abs_col ,
n,
p,
MOD(n, p) AS mod_col,
ROUND(m,1) AS round_colS
FROM samplemath;


-- 创建数学函数表
-- DDL ：创建表
USE  shop;

DROP TABLE IF EXISTS samplestr;
CREATE TABLE samplestr(
  str1 VARCHAR (40),
  str2 VARCHAR (40),
  str3 VARCHAR (40)
);

-- DML：插入数据
START TRANSACTION;
INSERT INTO samplestr (str1, str2, str3) VALUES ('opx',	'rt', NULL);
INSERT INTO samplestr (str1, str2, str3) VALUES ('abc', 'def', NULL);
INSERT INTO samplestr (str1, str2, str3) VALUES ('太阳',	'月亮', '火星');
INSERT INTO samplestr (str1, str2, str3) VALUES ('aaa',	NULL, NULL);
INSERT INTO samplestr (str1, str2, str3) VALUES (NULL, 'xyz', NULL);
INSERT INTO samplestr (str1, str2, str3) VALUES ('@!#$%', NULL, NULL);
INSERT INTO samplestr (str1, str2, str3) VALUES ('ABC', NULL, NULL);
INSERT INTO samplestr (str1, str2, str3) VALUES ('aBC', NULL, NULL);
INSERT INTO samplestr (str1, str2, str3) VALUES ('abc 哈哈',  'abc', 'ABC');
INSERT INTO samplestr (str1, str2, str3) VALUES ('abcdefabc', 'abc', 'ABC');
INSERT INTO samplestr (str1, str2, str3) VALUES ('micmic', 'i', 'I');
COMMIT;

-- 函数

SELECT SUBSTRING_INDEX('www.mysql.com', '.', 2);

SELECT SUBSTRING_INDEX('www.mysql.com', '.', -2);

SELECT SUBSTRING_INDEX('www.mysql.com', '.', 1);

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX('www.mysql.com', '.', 2), '.', -1);

SELECT CURRENT_DATE;
SELECT CURRENT_TIME;
SELECT CURRENT_TIMESTAMP;

SELECT CURRENT_TIMESTAMP AS now,
EXTRACT(YEAR   FROM CURRENT_TIMESTAMP) AS year,
EXTRACT(MONTH  FROM CURRENT_TIMESTAMP) AS month,
EXTRACT(DAY    FROM CURRENT_TIMESTAMP) AS day,
EXTRACT(HOUR   FROM CURRENT_TIMESTAMP) AS hour,
EXTRACT(MINUTE FROM CURRENT_TIMESTAMP) AS MINute,
EXTRACT(SECOND FROM CURRENT_TIMESTAMP) AS second;

SELECT CAST('0001' AS SIGNED INTEGER) AS int_col;
SELECT CAST('2009-12-14' AS DATE) AS date_col;
SELECT
COALESCE(NULL, 11) AS col_1,
COALESCE(NULL, 'hello world', NULL) AS col_2,
COALESCE(NULL, NULL, '2020-11-01') AS col_3;

-- 创建谓词查询表

-- DDL ：创建表
  CREATE TABLE samplelike(
      strcol VARCHAR(6) NOT NULL,
      PRIMARY KEY (strcol)
  );

-- DML ：插入数据
START TRANSACTION; -- 开始事务
INSERT INTO samplelike (strcol) VALUES ('abcddd');
INSERT INTO samplelike (strcol) VALUES ('dddabc');
INSERT INTO samplelike (strcol) VALUES ('abdddc');
INSERT INTO samplelike (strcol) VALUES ('abcdd');
INSERT INTO samplelike (strcol) VALUES ('ddabc');
INSERT INTO samplelike (strcol) VALUES ('abddc');
COMMIT; -- 提交事务

SELECT * FROM samplelike;

-- 前方一致：选取出“dddabc”

SELECT *
FROM samplelike
WHERE strcol LIKE 'ddd%';

-- 中间一致：选取出“abcddd”,“dddabc”,“abdddc”

SELECT *
FROM samplelike
WHERE strcol LIKE '%ddd%';

-- 后方一致：选取出“abcddd“

SELECT *
FROM samplelike
WHERE strcol LIKE '%ddd';

-- 选取销售单价为 100～ 1000 元的商品
SELECT product_name, sale_price
FROM product
WHERE sale_price BETWEEN 100 AND 1000;

-- 如果不想让结果中包含临界值，那就必须使用 `<` 和 `>`。
SELECT product_name, sale_price
FROM product
WHERE sale_price > 100
    AND sale_price < 1000;

-- 为了选取出某些值为 NULL 的列的数据，不能使用 `=`，而只能使用特定的谓词 **IS NULL**。
SELECT product_name, purchase_price
FROM product
WHERE purchase_price IS NULL;

-- 想要选取 NULL 以外的数据时，需要使用 `IS NOT NULL`。
SELECT product_name, purchase_price
FROM product
WHERE purchase_price IS NOT NULL;

-- 多个查询条件取并集时可以选择使用 `or` 语句。
-- 通过 OR 指定多个进货单价进行查询
SELECT product_name, purchase_price
FROM product
WHERE purchase_price = 320
    OR purchase_price = 500
    OR purchase_price = 5000;

SELECT product_name, purchase_price
FROM product
WHERE purchase_price IN (320, 500, 5000);

-- “进货单价不是 320 元、 500 元、 5000 元”的商品时，可以使用否定形式 NOT IN 来实现。
SELECT product_name, purchase_price
FROM product
WHERE purchase_price NOT IN (320, 500, 5000);


-- DDL ：创建表
DROP TABLE IF EXISTS shop_product;

CREATE TABLE shop_product(
  shop_id CHAR(4)     NOT NULL,
  shop_name VARCHAR(200) NOT NULL,
  product_id CHAR(4)      NOT NULL,
  quantity INTEGER      NOT NULL,
  PRIMARY KEY (shop_id, product_id) -- 指定主键
);

-- DML ：插入数据
START TRANSACTION; -- 开始事务
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000A', '东京', '0001', 30);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000A', '东京', '0002', 50);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000A', '东京', '0003', 15);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000B', '名古屋', '0002', 30);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000B', '名古屋', '0003', 120);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000B', '名古屋', '0004', 20);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000B', '名古屋', '0006', 10);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000B', '名古屋', '0007', 40);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000C', '大阪', '0003', 20);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000C', '大阪', '0004', 50);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000C', '大阪', '0006', 90);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000C', '大阪', '0007', 70);
INSERT INTO shop_product (shop_id, shop_name, product_id, quantity)
VALUES ('000D', '福冈', '0001', 100);
COMMIT; -- 提交事务


SELECT * FROM shop_product;

-- step1：取出大阪门店的在售商品 `product_id`
SELECT product_id
FROM shop_product
WHERE shop_id = '000C';

-- step2：取出大阪门店在售商品的销售单价 `sale_price`
SELECT product_name, sale_price
FROM product
WHERE product_id IN (SELECT product_id
                   FROM shop_product
                   WHERE shop_id = '000C');

-- 子查询展开后的结果
SELECT product_name, sale_price
FROM product
WHERE product_id IN ('0003', '0004', '0006', '0007');

-- NOT IN 使用子查询作为参数，取出未在大阪门店销售的商品的销售单价
SELECT product_name, sale_price
FROM product
WHERE product_id NOT IN (SELECT product_id
                       FROM shop_product
                       WHERE shop_id = '000A');

-- 使用 EXIST 选取出大阪门店在售商品的销售单价。
SELECT product_name, sale_price
FROM product AS p
WHERE EXISTS (SELECT *
           FROM shop_product AS sp
           WHERE sp.shop_id = '000C'
                 AND sp.product_id = p.product_id
           );

-- 更高效率的写法
SELECT product_name, sale_price
FROM product AS p
WHERE EXISTS (SELECT 1 -- 这里可以书写适当的常数
           FROM shop_product AS sp
           WHERE sp.shop_id = '000C'
               AND sp.product_id = p.product_id);