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mysql 基础知识
建库：

1. mysql> CREATE DATABASE IF NOT EXISTS bihuo_db_char
   
2.     -> DEFAULT CHARACTER SET utf8
   
3.     -> DEFAULT COLLATE utf8_chinese_ci;
   
4. Query OK, 1 row affected (0.03 sec)

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建表：create table 表名（）

1. create table student (id int ,
   
2. name varchar(255),
   
3. math_score int ,
   
4. english_score int,
   
5. mandarin_score  int,
   
6. primary key (`id`))
   
7. ENGINE=InnoDB DEFAULT CHARSET=utf8;
   

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插入数据

1. insert into student (name,math_score,english_score,mandarin_score) values
   
2. ('bihuo', 88, 99, 89);
   
3. 
   
4. insert into student (name,math_score,english_score,mandarin_score) values
   
5. ('bihuo1', 58, 99, 89);

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查询数据

1. select * from student;

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float 和 decimal 的区别