Not working correctly query

I want to make a query and use the value entered by the user in the edittext as condition is the where clause. In database helper.java class: The query is the following:

public Cursor patientHisto ( String value ) {
    SQLiteDatabase db = this.getWritableDatabase();
 Cursor res = db.rawQuery (" select dateap,diagnostic,prestreatment from patients_table, appointments_table, examinations_table where patients_table.id = appointments_table.idp and appointments_table.idap = examinations_table.id_ap and ID = ?  order by name, familyname asc"  , new String[] {value} );
        return res;
    }

In ExaminatFragment.java:

public class ExaminatFragment extends Fragment {
    DatabaseHelper myDB;
    EditText id_p;
    Button showhp;
     String value;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState){
    View v = inflater.inflate(R.layout.fragment_examinat, parent, false);
    myDB = new DatabaseHelper(getActivity());

    id_p = (EditText)v.findViewById(R.id.id_p_text);


    getPatHisto( );
    return v;
    }   

public void getPatHisto( ) {

     value = id_p.getText().toString();

    showhp.setOnClickListener(

                new View.OnClickListener() {

        @Override
        public void onClick(View v) {
        Cursor res = myDB.patientHisto(value);
        if (res.getCount() == 0){

    showMessage("Patient history", "No patient history found");
        return;

                    }


        StringBuffer buffer = new StringBuffer();
        while (res.moveToNext()){
                            buffer.append("Dateap:"+res.getString(0)+"\n");
                            buffer.append("Diagnostic:"+res.getString(1)+"\n");
                            buffer.append("Prestreatment:"+res.getString(2)+"\n\n");




                        }
                showMessage("Patient's history", buffer.toString());
                    }


                }
                );
                }






public void showMessage(String title, String Message){

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setCancelable(true);
        builder.setTitle(title);
        builder.setMessage(Message);
        builder.show();

    }

When running the application, selecting in the editext patientid and clicking on the button it gives me always: No patient history found , even if the patient has examination history. Please help.. thank you in advance