Your question is too vague, but I think you could have a look at this tutorial, it explains well how to establish a communication and exchange information between Android and a Php server : http://www.androidhive.info/2012/05/how-to-connect-android-with-php-mysql/
EDIT :
Basically, here is how you could do that : in your main activity, you will instanciate a class that inhererits AsyncTask :
AsyncTask Android example
http://developer.android.com/reference/android/os/AsyncTask.html
You will pass to this class a url to access your php web service. In this class, you will find a method called doInBackground. In this method, you will do all the processing to retrieve your data from your SQLite database :
http://www.androidhive.info/2011/11/android-sqlite-database-tutorial/
http://www.vogella.com/articles/AndroidSQLite/article.html
Then, you will have to build a JSON object that you will send to your web service :
http://www.vogella.com/articles/AndroidJSON/article.html
http://androidexample.com/JSON_Parsing_-_Android_Example/index.php?view=article_discription&aid=71&aaid=95
And then on your server side, you can use the first link I provided to get the json data and store it into MySQL