How to create web handler in php

See more:

ASP.NET

Mobile

PHP

MySQL

Android

My partner is creating an android app and I am working on its back-end side.
We need to fetch data from database located on the server to our app.
I am familiar to design web handler/web services to handle remote requests in asp.net.

Please guide me on how to create a web handler in PHP to retrieve some data from tables and send it to remote request device. Which one would be better to use PHP or ASP.net for our purpose?

I am uploading a sample program that I created in ASP.net to handle the requests (I guess this sample program has nothing to do with my question but still I believe it would help)

<%@ WebHandler Language="C#" Class="DefaultLocationHandler" %>

using System;
using System.Web;

public class DefaultLocationHandler : IHttpHandler {
    
    public void ProcessRequest (HttpContext context) {
        int username = Convert.ToInt32(context.Request.Params["username"].ToString());                                                                           
        decimal password =Convert .ToDecimal ( context.Request.Params["password"].ToString());
        decimal email =Convert .ToDecimal ( context.Request.Params["Email"].ToString());


        SqlConnection con = new SqlConnection("Data Source=103.21.58.192;Initial Catalog=Helper;User ID=avi_Helper;Password=xyz2515");
        con.Open();
        string str = @"Insert into [Helper].[dbo].[Default_Location]  
		      ([User_Number]
		      ,[Default_Latitude]
		      ,[Default_Longitude])
		     VALUES ('" + username + "'," + password + "," + email + ")";

        SqlCommand cmd = new SqlCommand(str, con);
        cmd.ExecuteNonQuery();
        con.Close();
        context.Response.Write("Inserted" + username);
    }
    
 
    public bool IsReusable {
        get {
            return false;
        }
    }
}