easily know php and mysql

This isn't a forum for teaching you how to program or how to use a particular language. When you actually do some work and can't figure out why something doesn't do what you expect, you can ask those questions here and probably get some help. Your question is waaaaaay too broad and vague for anyone to give you a particularly meaningful answer.
And please note that, in my opinion, there is no way to "easily understand" any programming language. Understanding comes with experience. Experience takes time and effort.