在mysql中创建纯数字数据库是不合标准的，默认会提示语法错误，但通过mysql转义符 ` 还是可以创建。

CREATE DATABASE 222;

报错：

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 '222' at line 1

# 加上转义符

CREATE DATABASE `222`;

成功。

# 查询语句

SELECT * FROM 222.aaa WHERE id = 1;

报错：
错误码: 1064

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 '222.aaa WHERE id = 1' at line 1

# 加上转义符查询

SELECT * FROM `222`.aaa WHERE id = 1;

可以查询

# 删除加转义符删除

DROP DATABASE `222`;