how to connect android app to sql server database......

Following steps
1. Create your own mysql database
2. Write your web service in PHP or .NET
Sample code

<?php
$host = '198.57.182.115';
$user = 'root';
$password = 'root';
$dbName = "db";

$link = mysql_connect($host, $user, $password);
mysql_select_db($dbName, $link);
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo "Connect successfully";
?>

3. Write your android code to call the web service to get the data

String responseBody = null;
     HttpClient httpclient = HttpsClient
             .getHttpsClient(new DefaultHttpClient());
     HttpPost httppost = new HttpPost("Link to your web sevice");
     try {
        // Execute HTTP Post Request
         ResponseHandler<String> responseHandler = new BasicResponseHandler();
         responseBody = httpclient.execute(httppost, responseHandler);
         Log.d("responseBody: ", responseBody);
     } catch (UnsupportedEncodingException e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
         return e.toString();
     } catch (ClientProtocolException e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
         return e.toString();
     } catch (JSONException e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
         return e.toString();
     } catch (Exception e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
         return e.toString();
     }

In above code, responseBody is the return data from webservice