使用数据库Use Database

USE db_name

设置当前数据库。Set the current database. 未显式指定数据库的所有后续命令将使用此数据库。All subsequent commands that do not explicitly specify a database will use this one. 如果提供的数据库不存在,则会引发异常。If the provided database does not exist, an exception is thrown. 默认的当前数据库是 defaultThe default current database is default.