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From: =?UTF-8?q?=E9=99=88=E6=A2=A6=E6=A2=A6?= <3195337478@qq.com>
Date: Thu, 19 Oct 2023 04:43:19 +0000
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-- 
Gitee


From 170c68b2514be7fad117a3ec6ae1227293d20c0b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=99=88=E6=A2=A6=E6=A2=A6?= <3195337478@qq.com>
Date: Thu, 19 Oct 2023 04:43:48 +0000
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Signed-off-by: 陈梦梦 <3195337478@qq.com>
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+##### 笔记
+
+```mysql
+索引
+1.普通索引
+create index 索引名 on 表名（列名）;
+2.唯一索引
+3.主键索引
+4.联合索引
+```
+
+
+
+##### 作业
+
+```mysql
+drop database if exists zy;
+create database zy charset utf8;
+use zy;
+-- -- 建立一个数据和表（id,name,phone,sex,hobby），想办法插入10万条数据，
+create table abc(
+id int primary key,
+name varchar(20),
+phone varchar(20),
+sex char(1),
+hobby varchar(20)
+);
+
+
+delimiter //
+create procedure prc_zy(in n int)
+begin
+declare sex char(1);
+declare hobby varchar(20);
+declare return_str varchar(20);
+declare `name` varchar(20);
+declare i int default 1;
+	while i<n do 
+		set sex='男';
+		set hobby ='打球';
+		set `name` ='王大锤';
+	-- 	set return_str=substring(chars_str,foolr(rand()*15),1);
+		insert into abc values (i,concat(`name`,i),i,sex,hobby);
+		set sex='女';
+		set i=i+1;
+		set `name` ='王大话';
+	-- 	set return_str=substring(chars_str,foolr(rand()*15),1);
+		set hobby ='sing';
+		insert into abc values (i, concat(`name`,i), i, sex, hobby);
+		set i=i+1;
+end while;
+end//
+delimiter;
+
+call prc_zy(100000);
+
+create database zy_1018 charset utf8;
+use zy_1018;
+-- --案例
+-- 
+-- 执行查询文件tb_user.sql，数据准备好了之后，完成如下需求：
+create table tb_user(
+	id int primary key auto_increment comment '主键',
+	name varchar(50) not null comment '用户名',
+	phone varchar(11) not null comment '手机号',
+	email varchar(100) comment '邮箱',
+	profession varchar(11) comment '专业',
+	age tinyint unsigned comment '年龄',
+	gender char(1) comment '性别 , 1: 男, 2: 女',
+	status char(1) comment '状态',
+	createtime datetime comment '创建时间'
+) comment '系统用户表';
+
+
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('吕布', '17799990000', 'lvbu666@163.com', '软件工程', 23, '1', '6', '2001-02-02 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('曹操', '17799990001', 'caocao666@qq.com', '通讯工程', 33, '1', '0', '2001-03-05 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('赵云', '17799990002', '17799990@139.com', '英语', 34, '1', '2', '2002-03-02 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('孙悟空', '17799990003', '17799990@sina.com', '工程造价', 54, '1', '0', '2001-07-02 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('花木兰', '17799990004', '19980729@sina.com', '软件工程', 23, '2', '1', '2001-04-22 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('大乔', '17799990005', 'daqiao666@sina.com', '舞蹈', 22, '2', '0', '2001-02-07 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('露娜', '17799990006', 'luna_love@sina.com', '应用数学', 24, '2', '0', '2001-02-08 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('程咬金', '17799990007', 'chengyaojin@163.com', '化工', 38, '1', '5', '2001-05-23 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('项羽', '17799990008', 'xiaoyu666@qq.com', '金属材料', 43, '1', '0', '2001-09-18 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('白起', '17799990009', 'baiqi666@sina.com', '机械工程及其自动化', 27, '1', '2', '2001-08-16 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('韩信', '17799990010', 'hanxin520@163.com', '无机非金属材料工程', 27, '1', '0', '2001-06-12 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('荆轲', '17799990011', 'jingke123@163.com', '会计', 29, '1', '0', '2001-05-11 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('兰陵王', '17799990012', 'lanlinwang666@126.com', '工程造价', 44, '1', '1', '2001-04-09 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('狂铁', '17799990013', 'kuangtie@sina.com', '应用数学', 43, '1', '2', '2001-04-10 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('貂蝉', '17799990014', '84958948374@qq.com', '软件工程', 40, '2', '3', '2001-02-12 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('妲己', '17799990015', '2783238293@qq.com', '软件工程', 31, '2', '0', '2001-01-30 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('芈月', '17799990016', 'xiaomin2001@sina.com', '工业经济', 35, '2', '0', '2000-05-03 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('嬴政', '17799990017', '8839434342@qq.com', '化工', 38, '1', '1', '2001-08-08 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('狄仁杰', '17799990018', 'jujiamlm8166@163.com', '国际贸易', 30, '1', '0', '2007-03-12 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('安琪拉', '17799990019', 'jdodm1h@126.com', '城市规划', 51, '2', '0', '2001-08-15 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('典韦', '17799990020', 'ycaunanjian@163.com', '城市规划', 52, '1', '2', '2000-04-12 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('廉颇', '17799990021', 'lianpo321@126.com', '土木工程', 19, '1', '3', '2002-07-18 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('后羿', '17799990022', 'altycj2000@139.com', '城市园林', 20, '1', '0', '2002-03-10 00:00:00');
+INSERT INTO tb_user (name, phone, email, profession, age, gender, status, createtime) VALUES ('姜子牙', '17799990023', '37483844@qq.com', '工程造价', 29, '1', '4', '2003-05-26 00:00:00');
+-- 1. name字段为姓名字段，该字段的值可能会重复，为该字段创建索引。
+create index index_name on tb_user(name);
+show index from tb_user;
+explain select * from tb_user where name='姜子牙';
+-- 2. phone手机号字段的值，是非空，且唯一的，为该字段创建唯一索引。
+create unique index index_phone on tb_user(phone);
+alter table tb_user modify phone char(11) unique not null;
+
+
+-- 3. 为profession、age、status创建联合索引。
+create index index_lianhe on tb_user(profession,age,status);
+-- 4. 为email建立合适的索引来提升查询效率。
+create index index_email on tb_user(email);
+explain select * from tb_user where email='37483844@qq.com';
+-- 5. 查看tb_user表的所有的索引数据。
+show index from tb_user;
+```
+
+<a href="https://smms.app/image/fgRTkywzP3BnX1E" target="_blank"><img src="https://s2.loli.net/2023/10/19/fgRTkywzP3BnX1E.png" alt="0b9fb2d73e5f7a9b15f065d33bb6982.png"></a>
+
+![e7eb1a63d6b7eefb29d81f4cae6d429.png](https://s2.loli.net/2023/10/19/TKqxvI39YnRFmVa.png)
-- 
Gitee