Database objects not getting executed

I am running the following thread in a service. But, if I have 3 or 4 rows of data in the database, the last one does not get executed. If I am having 4 rows of data, only 3 gets executed. Can anyone tell me what is the reason for this?

 new Thread(new Runnable() {
        @Override
        public void run() {

            List<Greetings>greetings = db.getAllGreetings();
                 if(db.getGreetingsCount()>0) {
                     do {
                         for (Greetings g : greetings) {
                             Calendar cal = Calendar.getInstance();
                             d1 = cal.get(Calendar.DAY_OF_MONTH);
                             d2 = cal.get(Calendar.MONTH);
                             d3 = cal.get(Calendar.YEAR);
                             t1 = cal.get(Calendar.HOUR);
                             t2 = cal.get(Calendar.MINUTE);
                             t3 = cal.get(Calendar.AM_PM);
                             if (t3 == 1) {
                                 t4 = "PM";
                             } else {
                                 t4 = "AM";
                             }
                             StringBuilder strt = new StringBuilder().append(t1).append(" : ").append(t2)
                                     .append(" ").append(t4);

                             tc = strt.toString();
                             StringBuilder builder = new StringBuilder().append(String.valueOf(d3) + "-").append((String.valueOf(d2 + 1)) + "-")
                                     .append(String.valueOf(d1));

                             d = builder.toString();
                             cdt = d + "\t" + tc;
                             //Log.d(cdt, "About to execute MyTask");
                             time = g.getTime();
                             date = g.getDate();
                             phone = g.getPhoneNumber();
                             msg = g.getMessage();
                             id = g.getID();
                             dnt = date + "\t" + time;
                             //Log.d(dnt, "About to execute MyTask");
                             if (dnt.equals(cdt)) {
                                 Intent aint = new Intent(getApplicationContext(), AlarmReceiver.class);

                                 aint.putExtra("msg", msg);
                                 aint.putExtra("phone", phone);
                                 aint.putExtra("id", id);
                                 PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(), id, aint, PendingIntent.FLAG_UPDATE_CURRENT);
                                 alarmManager.set(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), pendingIntent);
                                 db.deleteGreetings(g);
                             }

                         }
                         k = db.getGreetingsCount();

                     } while ( k !=0 );
                 }

        }
    }).start();
     return START_NOT_STICKY;