MySQL 8.4 Release Notes
本章讨论在使用 MySQL 时编写 SQL 语句以下元素的规则:This chapter discusses the rules for writing the following elements of SQL statements when using MySQL:
字面值,如字符串和数字Literal values such as strings and numbers
标识符,如数据库、表和列名Identifiers such as database, table, and column names
关键字和保留字Keywords and reserved words
用户定义和系统变量User-defined and system variables
表达式Expressions
查询属性Query attributes
注释Comments