在mysql命令行中执行
SET PASSWORD FOR ‘root‘@‘localhost‘ = PASSWORD(‘123456‘);
GRANT ALL PRIVILEGES ON *.* TO ‘root‘ @‘%‘ IDENTIFIED BY ‘123456‘ WITH GRANT OPTION;
flush privileges;
若以上方法行不通则用：
use mysql;
UPDATE user SET Password=PASSWORD(‘123456‘) where USER=‘root‘;
flush privileges;
数据库出现1045 access denied for user 'root'@'localhost' using password yes (转）
原文：http://www.cnblogs.com/lifeBuilder/p/5873157.html
