这是关于5.1版至5.1.2-alpha版MySQL数据库系统的参考手册。该手册不适用于旧版本MySQL软件，这是因为在MySQL 5.1和以前的版本存在很多功能性差异和其他差异。如果正在使用MySQL软件的较旧版本，请参阅MySQL 5.0参考手册，该手册涵盖了MySQL 5.0，或参阅MySQL 4.1参考手册，该手册涵盖了MySQL 4.1以及MySQL的所有早期版本。在手册的文本中，通过引用发布版本号（5.1.x），注明了MySQL 5.1的二级版本-This is about 5.1 to version 5.1.2-alpha version of MySQL database system reference manual. The handbook does not apply to older versions of MySQL software, This is because in MySQL 5.1 and previous versions, there are many functional differences and other differences. MySQL If you are using older versions of software, see the MySQL 5.0 reference manual, which covers the MySQL 5.0, or see the MySQL 4.1 reference manual, which covers MySQL 4.1 and all earlier versions of MySQL. The text in the manual, issued by reference the version number (5.1.x), indicated the two versions of MySQL 5.1