diff --git "a/\345\221\250\345\216\232\350\276\260/2023220 \347\254\254\344\270\200\346\254\241MySQL\344\275\234\344\270\232.md" "b/\345\221\250\345\216\232\350\276\260/2023220 \347\254\254\344\270\200\346\254\241MySQL\344\275\234\344\270\232.md" new file mode 100644 index 0000000000000000000000000000000000000000..86905997a37604ea19c93c2a74875b05f367abb5 --- /dev/null +++ "b/\345\221\250\345\216\232\350\276\260/2023220 \347\254\254\344\270\200\346\254\241MySQL\344\275\234\344\270\232.md" @@ -0,0 +1,446 @@ +# 笔记 + +## 创建数据库 + +```mysql +create database <数据库名>; +``` + +## 使用数据库 + +```mysql +use <数据库名>; +``` + +## 创建表格 + +```mysql +create table <表名>( + +); +``` + +## + +# 作业 + +--- + +## 第1题 + +1、创建数据库test01_market + +答案： + +```mysql +create database if not exists test01_market; +use test01_market; +``` + +--- + +2、创建表格customers + +| 字段名 | 数据类型 | +| --------- | ----------- | +| c_num | int（11） | +| c_name | varchar(50) | +| c_contact | varchar(50) | +| c_city | varchar(50) | +| c_birth | date | + +答案： + +```mysql +create table if not exists customers( + c_num int(11), + c_name varchar(50), + c_contact varchar(50), + c_city varchar(50), + c_birth date +); +``` + +--- + +**要求3：**将c_contact字段移动到c_birth字段后面 + +答案： + +```mysql +alter table customers modify c_contact varchar(50) after c_birth; +``` + +--- + +**要求4：**将c_name字段数据类型改为 varchar(70) + +答案： + +```mys +alter table customers modify c_name varchar(70); +``` + +--- + +**要求5：**将c_contact字段改名为c_phone + +答案： + +```mysql +alter table customers change c_contact c_phone varchar(50); +``` + +--- + +**要求6：**增加c_gender字段到c_name后面，数据类型为char(1) + +答案： + +```mysq +alter table customers add c_gender char(1) after c_name; +``` + +--- + +**要求7：**将表名改为customers_info + +答案： + +```mysq +alter table customers rename to customers_info; +``` + +--- + +**要求8：**删除字段c_city + +答案： + +```mysql +alter table customers_info drop c_city; +``` + +## 第2题 + +1、创建数据库test02_library + +答案： + +```mysql +create database if not exists test02_library; +use test02_library; +``` + +--- + +2、创建表格books + +| 字段名 | 字段说明 | 数据类型 | 允许为空 | 唯一 | +| ------- | -------- | ------------- | -------- | ---- | +| b_id | 书编号 | int(11) | 否 | 是 | +| b_name | 书名 | varchar（50） | 否 | 否 | +| authors | 作者 | varchar(100) | 否 | 否 | +| price | 价格 | float | 否 | 否 | +| pubdate | 出版日期 | year | 否 | 否 | +| note | 说明 | varchar(100) | 是 | 否 | +| num | 库存 | int(11) | 否 | 否 | + +答案： + +```mysql +create table if not exists books( + b_id int(11), + b_name varchar(50), + authors varchar(100), + price float, + pubdate year, + note varchar(100), + num int(11) +); +``` + +--- + +3、向books表中插入记录 + +1） 指定所有字段名称插入第一条记录 + +答案： + +```mys +insert into books(b_id,b_name,`authors`,price,pubdate,note,num) values(1,'Tal of AAA','Dickes',23,1995,'novel',11); +``` + +--- + +2）不指定字段名称插入第二记录 + +答案： + +```mysql +insert into books values(2,'EmmaT','Janelura',35,1993,'joke',22); +``` + +--- + +3）同时插入多条记录（剩下的所有记录） + +| b_id | b_name | authors | price | pubdate | note | num | +| ---- | ------------- | --------------- | ----- | ------- | -------- | ---- | +| 1 | Tal of AAA | Dickes | 23 | 1995 | novel | 11 | +| 2 | EmmaT | Jane lura | 35 | 1993 | joke | 22 | +| 3 | Story of Jane | Jane Tim | 40 | 2001 | novel | 0 | +| 4 | Lovey Day | George Byron | 20 | 2005 | novel | 30 | +| 5 | Old land | Honore Blade | 30 | 2010 | law | 0 | +| 6 | The Battle | Upton Sara | 30 | 1999 | medicine | 40 | +| 7 | Rose Hood | Richard haggard | 28 | 2008 | cartoon | 28 | + +答案： + +```mysql +insert into books(b_id,b_name,authors,price,pubdate,note,num) values(3,'Story of Jane','Jane Tim',40,2001,'novel',0),(4,'Lovey Day','George Byron',20,2005,'novel',30),(5,'Old land','Honore Blade',30,'2010','law',0),(6,'The Battle','Upton Sara',30,'1999','medicine',40),(7,'Rose Hood','Richard haggard',28,'2008','cartoon',28); +``` + +--- + +4、将小说类型(novel)的书的价格都增加5。 + +答案： + +```mysql +update books set price = price+5 where note = 'novel'; +``` + +--- + +5、将名称为EmmaT的书的价格改为40。 + +答案： + +```mysql +update books set price = 40 where b_name = 'EmmaT'; +``` + +--- + +6、删除库存为0的记录 + +答案： + +```mysql +delete from books where num = 0; +``` + + + +## 第3题 + +1、创建数据库test03_bookstore + +答案： + +```mysql +create database if not exists test03_bookstore; +use test03_bookstore; +``` + +--- + +2、创建book表 + +```mysql ++----------+--------------+------+-----+---------+----------------+ +| Field | Type | Null | Key | Default | Extra | ++----------+--------------+------+-----+---------+----------------+ +| id | int(11) | NO | PRI | NULL | auto_increment | +| title | varchar(100) | NO | | NULL | | +| author | varchar(100) | NO | | NULL | | +| price | double(11,2) | NO | | NULL | | +| sales | int(11) | NO | | NULL | | +| stock | int(11) | NO | | NULL | | +| img_path | varchar(100) | NO | | NULL | | ++----------+--------------+------+-----+---------+----------------+ +``` + +答案： + +```mysql +create table if not exists book( + id int(11), + title varchar(100), + author varchar(100), + price double(11,2), + sales int(11), + stock int(11), + img_path varchar(100) +); +``` + +--- + +尝试添加部分模拟数据，参考示例如下： + +```mysql ++----+-------------+------------+-------+-------+-------+----------------------------+ +| id | title | author | price | sales | stock | img_path | ++----+-------------+------------+-------+-------+-------+-----------------------------+ +| 1 | 解忧杂货店 | 东野圭吾 | 27.20 | 102 | 98 | upload/books/解忧杂货店.jpg | +| 2 | 边城 | 沈从文 | 23.00 | 102 | 98 | upload/books/边城.jpg | ++----+---------------+------------+-------+-------+-------+----------------------------+ +``` + +答案： + +```mysql +insert into book(id,title,author,price,sales,stock,img_path) values(1,'解忧杂货店','东野圭吾',27.20,102,98,'upload/books/解忧杂货店.jpg'),(2,'边城','沈从文',23.00,102,98,'upload/books/边城.jpg'); + +``` + +--- + +3、创建用户表users，并插入数据 + +```mysql ++----------+--------------+------+-----+---------+----------------+ +| Field | Type | Null | Key | Default | Extra | ++----------+--------------+------+-----+---------+----------------+ +| id | int(11) | NO | PRI | NULL | auto_increment | +| username | varchar(100) | NO | UNI | NULL | | +| password | varchar(100) | NO | | NULL | | +| email | varchar(100) | YES | | NULL | | ++----------+--------------+------+-----+---------+----------------+ +``` + +答案： + +```mysql +create table if not exists users( + id int(11), + username varchar(100), + password varchar(100), + email varchar(100) +); +``` + +--- + +尝试添加部分模拟数据，参考示例如下： + +```mysql ++----+----------+----------------------------------+--------------------+ +| id | username | password | email | ++----+----------+----------------------------------+--------------------+ +| 1 | admin | 112233 | admin@mxdx.com | ++----+----------+----------------------------------+--------------------+ +``` + +答案： + +```mysql +insert into users values(1,'admin',112233,'admin@mxdx.com'); + +``` + +--- + +4、创建订单表orders + +```mysql ++--------------+--------------+------+-----+---------+-------+ +| Field | Type | Null | Key | Default | Extra | ++--------------+--------------+------+-----+---------+-------+ +| id | varchar(100) | NO | PRI | NULL | | +| order_time | datetime | NO | | NULL | | +| total_count | int(11) | NO | | NULL | | +| total_amount | double(11,2) | NO | | NULL | | +| state | int(11) | NO | | NULL | | +| user_id | int(11) | NO | MUL | NULL | | ++--------------+--------------+------+-----+---------+-------+ +``` + +答案： + +```mysql +create table if not exists orders( + id varchar(100), + order_time datetime, + total_count int(11), + total_amount double(11,2), + stte int(11), + user_id int(11) +); +``` + +--- + +尝试添加部分模拟数据，参考示例如下： + +```mysql ++----------------+---------------------+-------------+--------------+-------+---------+ +| id | order_time | total_count | total_amount | state | user_id | ++----------------+---------------------+-------------+--------------+-------+---------+ +| 15294258455691 | 2018-06-20 00:30:45 | 2 | 50.20 | 0 | 1 | ++----------------+---------------------+-------------+--------------+-------+---------+ +``` + +答案： + +```mysql +insert into orders values(15294258455691,'2018-06-20 00:30:45',2,50.20,0,1); + +``` + +--- + +5、创建订单明细表order_items + +```mysql ++----------+--------------+------+-----+---------+----------------+ +| Field | Type | Null | Key | Default | Extra | ++----------+--------------+------+-----+---------+----------------+ +| id | int(11) | NO | PRI | NULL | auto_increment | +| count | int(11) | NO | | NULL | | +| amount | double(11,2) | NO | | NULL | | +| title | varchar(100) | NO | | NULL | | +| author | varchar(100) | NO | | NULL | | +| price | double(11,2) | NO | | NULL | | +| img_path | varchar(100) | NO | | NULL | | +| order_id | varchar(100) | NO | MUL | NULL | | ++----------+--------------+------+-----+---------+----------------+ +``` + +答案： + +```mysql +create table if not exists order_items( + id int(11), + count int(11), + amount double(11,2), + title varchar(100), + author varchar(100), + price double(11,2), + img_path varchar(100), + order_id varchar(100) +); +``` + +--- + +尝试添加部分模拟数据，参考示例如下： + +```mysql ++----+-------+--------+---------+---------+-------+----------------+----------------+ +| id |count| amount| title | author | price | img_path | order_id | ++----+-------+--------+------------+----------+-------+----------------+----------------+ +| 1 | 1 | 27.20| 解忧杂货店 | 东野圭吾 | 27.20 | static/img/default.jpg|15294258455691 | +| 2 | 1 | 23.00| 边城 | 沈从文 | 23.00 | static/img/default.jpg|15294258455691 | ++----+-------+--------+------------+----------+-------+------------+----------------+ +``` + +答案： + +```mysql +insert into order_items(id,count,amount,title,author,price,img_path,order_id) values(1,1,27.20,'解忧杂货店','东野圭吾',27.20,'static/img/default.jpg',15294258455691),(2,1,23.00,'边城','沈从文',23.00,'static/img/default.jpg',15294258455691); +``` +