java - How to filter database output? (android PHP) -

i building mobile app in user logs in , outputs contents of database table named "announcements".

what i'm trying filter out these output based on "department" column "accounts" table in users stored.

the "announcements" table has column named "receiver".

the contents show if "department" column of user logged in has same value "receiver column" of "announcements" column or if value of receiver "all".

how do this?

my php script

<?php $host="localhost"; //replace database hostname  $username="root"; //replace database username  $password=""; //replace database password  $db_name="sunshinedb"; //replace database name  $con=mysql_connect("$host", "$username", "$password")or die("cannot connect");  mysql_select_db("$db_name")or die("cannot select db"); $sql = "select * announcement";  $result = mysql_query($sql); $json = array();  if(mysql_num_rows($result)){     while($row=mysql_fetch_assoc($result)){         $json['services'][]=$row;     } } mysql_close($con); echo json_encode($json);  ?> 

java class

jsonobject jsonobject; jsonarray jsonarray; listview listview;  arraylist<hashmap<string, string>> arraylist; progressdialog mprogressdialog;  jsonparser jsonparser = new jsonparser(); string email;  string[] services;  private string url = "http://10.0.3.2/sunshine-ems/services.php";  string user_id;  // json node names private static final string tag_trans_id = "announcement_id"; private static final string tag_date = "date"; private static final string tag_services = "title";  public void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.videos_layout);      // listview     listview lv = getlistview();      lv.setonitemclicklistener(new android.widget.adapterview.onitemclicklistener() {         @override         public void onitemclick(adapterview<?> arg0, view view, int arg2,                 long arg3) {              intent = new intent(getapplicationcontext(),                     single_list.class);              string transaction_id = ((textview) view                     .findviewbyid(r.id.transac_id)).gettext().tostring();              i.putextra("announcement_id", transaction_id);              startactivity(i);         }     });      new downloadjson().execute(); }  // downloadjson asynctask private class downloadjson extends asynctask<string, string, string> {      @override     protected void onpreexecute() {         super.onpreexecute();         // create progressdialog         mprogressdialog = new progressdialog(videosactivity.this);         // set progressdialog title         mprogressdialog.settitle("loading services");         // set progressdialog message         mprogressdialog.setmessage("loading...");         mprogressdialog.setindeterminate(false);         // show progressdialog         mprogressdialog.show();     }      @override     protected string doinbackground(string... params) {          jsonobject json = jsonfunctions.getjsonfromurl(url);          // check log cat json reponse         log.d("service history ", json.tostring());          // create array         arraylist = new arraylist<hashmap<string, string>>();          try {             // locate array name             jsonarray = json.getjsonarray("services");              (int = 0; < jsonarray.length(); i++) {                 hashmap<string, string> map = new hashmap<string, string>();                 json = jsonarray.getjsonobject(i);                  string transac_id = json.getstring(tag_trans_id);                 string date = json.getstring(tag_date);                 string service = json.getstring(tag_services);                  // retrive json objects                 map.put(tag_services, service);                 map.put(tag_date, date);                 map.put(tag_trans_id, transac_id);                  // set json objects array                 arraylist.add(map);             }         } catch (jsonexception e) {             log.e("error", e.getmessage());             e.printstacktrace();         }         return null;     }      @override     protected void onpostexecute(string file_url) {         mprogressdialog.dismiss();         // updating ui background thread         runonuithread(new runnable() {             public void run() {                  /**                  * updating parsed json data listview                  * */                 listadapter adapter = new simpleadapter(                         videosactivity.this, arraylist,                         r.layout.listview_services, new string[] {                                 tag_trans_id, tag_services, tag_date },                         new int[] { r.id.transac_id, r.id.txt_service,                                 r.id.txt_date });                 // updating listview                 setlistadapter(adapter);              }         });      } } 

you not making filtering anywhere in code...

the steps should these ones (in order) :

1. android side : calling webservice (php code) user's department (in or post parameter)
2. ws side : requesting database select * announcement receiver = '<department'> or receiver = 'all' department user's department
3. ws side : construct json response
4. android side : process json response display results

the advantages of making :

1. limit number of data transfered (limit network consumption on android device , limit load on php server)
2. limit number of data processed android side (limit load of android app : it's not desktop app ! never forgive !)

ps : reading post , comment, think should these points before starting make app : sql request, php mysql access (as pointed out @jay blanchard), web services , http protocol, android asynctask