昨天回顾
1. 什么是数据库？
存储数据的仓库
2. 为啥使用数据库？
3. 数据库的分类？
- 关系型数据库
MySQL, maridb, oracle,SQLServer, DB2, sqllite
- 非关系型数据库 （{key:value}） value可以是任何 的数据类型
redis，mongodb，memcache
4. 架构：
mysql的客户端 mysql的服务端
5. 安装：
windows的安装
a.解压
b.初始化数据
c.启动
d.将mysqld的服务制作成window的服务
linux的安装
6. 初是MySQL：
数据库（文件夹）：
增
create database 数据库名 charset utf8;
删
drop database 数据库名;
改
查
show databases;
使用：
use 数据库名
数据表（文件）：
增删改查
数据行（记录）：
增删改查
操作表
# 增
# 语法：
# create table 表名(
# 字段名 列类型 [可选的参数], ### 记住加逗号
# 字段名 列类型 [可选的参数], ### 记住加逗号
# 字段名 列类型 [可选的参数] ### 最后一行不加逗号
# .....
# )charset=utf8; #### 后面加分号
#
# 列约束：（*********************）
#
# auto_increment : 自增 1
# primary key : 主键索引，加快查询速度, 列的值不能重复
# NOT NULL 标识该字段不能为空
# DEFAULT 为该字段设置默认值
#
# 例子1：
# create table t1(
# id int,
# name char(5)
# )charset=utf8;
#
# Query OK, 0 rows affected (0.72 sec) #### 如果回显是queryok，代表创建成功
#
# 增加数据：
# 语法：
# insert into 表名 (列1, 列2) values (值1,'值2');
# 例子：
# insert into t1 (id, name) values (1, 'zekai');
# insert into t1 (id, name) values (1, 'zekai2');
# 查询数据：
# 语法：
# select 列1, 列2 from 表名; （*代表查询所有的列）
# 例子：
# mysql> select * from t1;
# +------+-------+
# | id | name |
# +------+-------+
# | 1 | zekai |
# +------+-------+
# 1 row in set (0.00 sec)
#
# 例子2:
#
# create table t2(
# id int auto_increment primary key,
# name char(10)
# )charset=utf8;
#
#
#
#
# insert into t2 (name) values ('zekai1');
#
# 例子3: (推荐)
# create table t3(
# id int unsigned auto_increment primary key,
# name char(10) not null default 'xxx',
# age int not null default 0
# )charset=utf8;
#
# mysql> insert into t3 (age) values (10);
# Query OK, 1 row affected (0.05 sec)
#
# mysql> select * from t3;
# +----+------+-----+
# | id | name | age |
# +----+------+-----+
# | 1 | xxx | 10 |
# +----+------+-----+
#
#
# 列类型： （********************）
#
# create table 表名(
# 字段名 列类型 unsigned [可选的参数], ### 记住加逗号
# 字段名 列类型 [可选的参数], ### 记住加逗号
# 字段名 列类型 [可选的参数] ### 最后一行不加逗号
# .....
# )charset=utf8; #### 后面加分号
#
# - 数字
# - 整型
# tinyint
# smallint
# int （************************） 推荐使用
# mediumint
# bigint
#
# a.整数类型
# b.取值范围
# c.unsigned 加上代表不能取负数 只适用于整型
#
# 应用场景：
# 根据公司业务的场景，来选取合适的类型
#
# - 浮点型 （***********）
# create table t5(
# id int auto_increment primary key,
# salary decimal(16,10),
# num float
# )charset=utf8;
#
# float: 不一定精确
# decimal: 非常的精确的数字 (5000.23) decimal(6, 2) m是数字总个数（负号不算），d是小数点后个数。
#
# 正好 10 位：
# mysql> insert into t5 (salary, num) values (500023.2312345678, 5000.2374837284783274832);
# Query OK, 1 row affected (0.04 sec)
#
# mysql> select * from t5;
# +----+-------------------+---------+
# | id | salary | num |
# +----+-------------------+---------+
# | 1 | 500023.2312345678 | 5000.24 |
# +----+-------------------+---------+
# 1 row in set (0.00 sec)
#
# 少于10位：
# mysql> insert into t5 (salary, num) values (500023.231234567, 5000.2374837284783274832);
# Query OK, 1 row affected (0.04 sec)
#
# mysql> select * from t5;
# +----+-------------------+---------+
# | id | salary | num |
# +----+-------------------+---------+
# | 1 | 500023.2312345678 | 5000.24 |
# | 2 | 500023.2312345670 | 5000.24 |
# +----+-------------------+---------+
#
# 多于10位：
# mysql> insert into t5 (salary, num) values (500023.23123456789, 5000.2374837284783274832);
# Query OK, 1 row affected, 1 warning (0.03 sec)
#
# mysql> select * from t5;
# +----+-------------------+---------+
# | id | salary | num |
# +----+-------------------+---------+
# | 1 | 500023.2312345678 | 5000.24 |
# | 2 | 500023.2312345670 | 5000.24 |
# | 3 | 500023.2312345679 | 5000.24 |
# +----+-------------------+---------+
#
# - 字符串
#
# - char(长度) ： 定长
# create table t6(
# id unsigned int auto_increment primary key,
# name char(10) not null default 'xxx',
# )charset=utf8;
#
#
# - varchar(长度)：变长
# create table t6(
# id int auto_increment primary key,
# name varchar(10) not null default 'xxx'
# )charset=utf8;
#
# mysql> insert into t6 (name) values ('hello');
# Query OK, 1 row affected (0.03 sec)
#
# mysql> select * from t6;
# +----+-------+
# | id | name |
# +----+-------+
# | 1 | hello |
# +----+-------+
# 1 row in set (0.00 sec)
#
# mysql> insert into t6 (name) values ('hellodbsabdsjabjdsa');
# ERROR 1406 (22001): Data too long for column 'name' at row 1
#
# 区别：
# char: 定长， 无论插入的字符是多少个，永远固定占规定的长度
# 场景：
# 1. 身份证
# 2. 手机号 char(11)
# 3. md5加密之后的值，比如密码 等 char(32)
#
# varchar: 变长， 根据插入的字符串的长度来计算所占的字节数，但是有一个字节是用来保存字符串的大小的
#
# 注意：如果， 不能确定插入的数据的大小， 一般建议使用 varchar(255)
#
# - 时间日期类型
# YEAR
# YYYY（1901/2155）
#
# DATE
# YYYY-MM-DD（1000-01-01/9999-12-31）
#
# TIME
# HH:MM:SS（'-838:59:59'/'838:59:59'）
#
# DATETIME (***************************)
#
# YYYY-MM-DD HH:MM:SS（1000-01-01 00:00:00/9999-12-31 23:59:59 Y）
#
# TIMESTAMP
#
# YYYYMMDD HHMMSS（1970-01-01 00:00:00/2037 年某时）
#
# 例子：
# create table t8(
# d date,
# t time,
# dt datetime
# );
# mysql> insert into t8 values(now(),now(),now());
# Query OK, 1 row affected, 1 warning (0.08 sec)
#
# mysql> select * from t8;
# +------------+----------+---------------------+
# | d | t | dt |
# +------------+----------+---------------------+
# | 2019-10-29 | 10:49:51 | 2019-10-29 10:49:51 |
# +------------+----------+---------------------+
# 1 row in set (0.00 sec)
# insert into t8 values(now(),now(),now());
#
# - 枚举
# 列出所有的选项
#
# create table t9 (
# id int auto_increment primary key,
# gender enum('male','female')
# )charset utf8;
#
# mysql> insert into t9 (gender) values ('male');
# Query OK, 1 row affected (0.04 sec)
#
# mysql> insert into t9 (gender) values ('female');
# Query OK, 1 row affected (0.03 sec)
#
# mysql> insert into t9 (gender) values ('dshajjdsja');
#
#
#
# 改
# 1. 修改表名
# ALTER TABLE 旧表名 RENAME 新表名;
#
# mysql> alter table t8 rename t88;
# Query OK, 0 rows affected (0.19 sec)
#
# 2. 增加字段
# ALTER TABLE 表名
# ADD 字段名 列类型 [可选的参数],
# ADD 字段名 列类型 [可选的参数];
#
# mysql> alter table t88 add name varchar(32) not null default '';
# Query OK, 0 rows affected (0.82 sec)
# Records: 0 Duplicates: 0 Warnings: 0
#
# 上面添加的列永远是添加在最后一列之后
#
# ALTER TABLE 表名
# ADD 字段名 列类型 [可选的参数] FIRST;
#
# mysql> alter table t88 add name3 varchar(32) not null default '' first;
# Query OK, 0 rows affected (0.83 sec)
# Records: 0 Duplicates: 0 Warnings: 0
#
#
# ALTER TABLE 表名
# ADD 字段名 列类型 [可选的参数] AFTER 字段名;
# mysql> alter table t88 add name4 varchar(32) not null default '' after d;
# Query OK, 0 rows affected (0.68 sec)
# Records: 0 Duplicates: 0 Warnings: 0
#
# 3. 删除字段
# ALTER TABLE 表名 DROP 字段名;
#
# mysql> alter table t88 drop name4;
# Query OK, 0 rows affected (0.66 sec)
# Records: 0 Duplicates: 0 Warnings: 0
#
# 4. 修改字段
# ALTER TABLE 表名 MODIFY 字段名 数据类型 [完整性约束条件…];
#
# mysql> alter table t88 modify name2 char(20);
# Query OK, 1 row affected (0.88 sec)
# Records: 1 Duplicates: 0 Warnings: 0
#
#
# ALTER TABLE 表名 CHANGE 旧字段名 新字段名 新数据类型 [完整性约束条件…];
#
# mysql> alter table t88 change name2 name22 varchar(32) not null default '';
# Query OK, 1 row affected (0.82 sec)
# Records: 1 Duplicates: 0 Warnings: 0
#
# mysql> alter table t88 change name22 name23;
# ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
#
# 删
# drop table 表名; #### 线上禁用
# mysql> drop table t9;
# Query OK, 0 rows affected (0.18 sec)
# 查
# mysql> show tables;
# +----------------+
# | Tables_in_test |
# +----------------+
# | t1 |
# +----------------+
# 1 row in set (0.00 sec)
#
# 复制表结构：
# mysql> ## 1. 查看t88表的创建语句
# mysql> show create table t88;
# +-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
# | Table | Create Table |
# +-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
# | t88 | CREATE TABLE `t88` (
# `name3` varchar(32) NOT NULL DEFAULT '',
# `d` date DEFAULT NULL,
# `t` time DEFAULT NULL,
# `dt` datetime DEFAULT NULL,
# `name` varchar(32) NOT NULL DEFAULT '',
# `name22` varchar(32) NOT NULL DEFAULT ''
# ) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
# +-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
# 1 row in set (0.01 sec)
#
# mysql> ## 2. like
# mysql> create table t89 like t88;
# Query OK, 0 rows affected (0.33 sec)
操作表数据行
# 增
# 增加数据：
# 语法：
# insert into 表名 (列1, 列2) values (值1,'值2');
# 例子：
# insert into t1 (id, name) values (1, 'zekai');
# insert into t1 (id, name) values (1, 'zekai2');
# insert into t1 (id, name) values (1, 'zekai2'),(2, 'zekai3'),(3,'zekai4');
#
# mysql> insert into t66 (name) select name from t6;
# Query OK, 4 rows affected (0.09 sec)
# Records: 4 Duplicates: 0 Warnings: 0
#
#
# 删
# delete from 表名 where 条件;
# mysql> delete from t5 where id=1;
# mysql> delete from t5 where id>1;
# mysql> delete from t5 where id>=1;
# mysql> delete from t5 where id<1;
# mysql> delete from t5 where id<=1;
# mysql> delete from t5 where id>=1 and id<10;
# Query OK, 1 row affected (0.06 sec)
#
# delete from 表名; 删除表中所有的数据
#
# mysql> insert into t5 (salary, num) values (500023.2312345679, 5000.24);
# Query OK, 1 row affected (0.08 sec)
#
# mysql> select * from t5;
# +----+-------------------+---------+
# | id | salary | num |
# +----+-------------------+---------+
# | 4 | 500023.2312345679 | 5000.24 |
# +----+-------------------+---------+
# 1 row in set (0.00 sec)
#
# truncate 表名; #### 没有where条件的
# mysql> truncate t5;
# Query OK, 0 rows affected (0.25 sec)
#
# mysql> select * from t5;
# Empty set (0.00 sec)
#
# mysql> insert into t5 (salary, num) values (500023.2312345679, 5000.24);
# Query OK, 1 row affected (0.06 sec)
#
# mysql> select * from t5;
# +----+-------------------+---------+
# | id | salary | num |
# +----+-------------------+---------+
# | 1 | 500023.2312345679 | 5000.24 |
# +----+-------------------+---------+
# 1 row in set (0.00 sec)
#
# 区别：
# 1. delete之后，插入数据从上一次主键自增加1开始， truncate则是从1开始
# 2. delete删除， 是一行一行的删除， truncate：全选删除 truncate删除的速度是高于delete的
#
#
#
# 改
# update 表名 set 列名1=新值1,列名2=新值2 where 条件;
# mysql> update t66 set name='xxxx' where id=30;
# Query OK, 1 row affected (0.04 sec)
# Rows matched: 1 Changed: 1 Warnings: 0
#
# mysql> update t66 set name='xxxx' where id<30;
# mysql> update t66 set name='xxxx' where id<=30;
# mysql> update t66 set name='xxxx' where id>=30;
# mysql> update t66 set name='xxxx' where id>30;
# mysql> update t66 set name='xxxx' where id>20 and id<32;
# mysql> update t66 set name='xxxx' where id>20 or name='zekai';
#
# Query OK, 1 row affected (0.04 sec)
# Rows matched: 1 Changed: 1 Warnings: 0
#
#
# 查
#
# 语法：
# select 列1, 列2 from 表名; （*代表查询所有的列）
# select * from 表名; （*代表查询所有的列）
# select * from t66 where id>30 and id<40;
# select * from t66 where id>30;
# select * from t66 where id<30;
# select * from t66 where id<=30;
# select * from t66 where id>=30;
# select * from t66 where id!=30;
# select * from t66 where id<>30;
# mysql> select * from t1;
# +------+-------+
# | id | name |
# +------+-------+
# | 1 | zekai |
# +------+-------+
# 1 row in set (0.00 sec)
#
# between..and...: 取值范围是闭区间
#
# select * from t66 where id between 30 and 40;
# mysql> select * from t66 where id between 31 and 33;
# +----+--------+
# | id | name |
# +----+--------+
# | 31 | dsadsa |
# | 32 | dsadsa |
# | 33 | dsadsa |
# +----+--------+
#
# 避免重复DISTINCT
# mysql> select distinct name from t66;
# +--------+
# | name |
# +--------+
# | xxxx |
# | hds |
# | dsadsa |
# +--------+
# 3 rows in set (0.00 sec)
#
# 通过四则运算查询 （不要用）
# mysql> select name, age*10 from t3;
# +------+--------+
# | name | age*10 |
# +------+--------+
# | xxx | 100 |
# +------+--------+
# 1 row in set (0.01 sec)
#
# mysql> select name, age*10 as age from t3;
# +------+-----+
# | name | age |
# +------+-----+
# | xxx | 100 |
# +------+-----+
# 1 row in set (0.02 sec)
#
# in(80,90,100):
#
# mysql> select * from t66 where id in (23,34,11);
# +----+------+
# | id | name |
# +----+------+
# | 11 | xxxx |
# | 23 | hds |
# +----+------+
# 2 rows in set (0.04 sec)
#
# like : 模糊查询
# 以x开头：
# mysql> select * from t66 where name like 'x%';
# +----+------+
# | id | name |
# +----+------+
# | 1 | xxxx |
# | 2 | xxxx |
# | 3 | xxxx |
# | 4 | xxxx |
# | 8 | xxxx |
# | 9 | xxxx |
# | 10 | xxxx |
# | 11 | xxxx |
# | 15 | xxxx |
# | 16 | xxxx |
# | 17 | xxxx |
# | 18 | xxxx |
# | 30 | xxxx |
# +----+------+
# 13 rows in set (0.05 sec)
#
# 以x结尾：
# mysql> select * from t66 where name like '%x';
# +----+------+
# | id | name |
# +----+------+
# | 1 | xxxx |
# | 2 | xxxx |
# | 3 | xxxx |
# | 4 | xxxx |
# | 8 | xxxx |
# | 9 | xxxx |
# | 10 | xxxx |
# | 11 | xxxx |
# | 15 | xxxx |
# | 16 | xxxx |
# | 17 | xxxx |
# | 18 | xxxx |
# | 30 | xxxx |
# +----+------+
# 13 rows in set (0.00 sec)
#
# 包含x的：
# mysql> select * from t66 where name like '%x%';
#
# 不让用