Question: I fetched data dynamically from from MySQL using a drop down menu through Ajax which was successful but when I echo the array values, instead of giving me the list of emails it was showing just symbols.

Take a look at the image below:
[![enter image description here](https://i.stack.imgur.com/v3TgI.png)](https://i.stack.imgur.com/v3TgI.png)

From the Email List, those are the symbols that were echo out.

here is my php code

```
if(isset($_POST["confirm_no"])){

    $d = $_POST['confirm_no'];
    $query = mysqli_query($mysqli, "select * from jobseeker WHERE confirm_no LIKE  '$d%'");

    //Display  list
    if(mysqli_num_rows($query) > 0){
          $row = mysqli_fetch_array($query);
            foreach ($row as $r) {
            $emailArr[] = $r["mails"];
        }
         $emails = implode(";", $emailArr);

        echo $emails;

    }else{
        echo 'No email for this selection.';
    }
}

```

And the jQuery

```
$(document).ready(function(){ 

$('#smode').change(function(){
var confirm_no = $(this).val();
$.ajax({
   type:'POST',
  data:"confirm_no="+confirm_no,
   url:'get_email.php',
   success:function(data){
       $('#emaillist').val(data);
   } 

});
});
});

```

Why is it echoing out this symbols?

Answer: 
It's because the values of `result` and `odd` are "null". Firebase does not support Null values. Checkout out [this question](https://stackoverflow.com/questions/27580844/firebase-wont-save-keys-with-null-values). That question references the documentation for Firebase, which includes this line:

*Passing null for the new value is equivalent to calling remove(); all data at this location or any child location will be deleted.*
I seems like Firebase Realtime Database does not like null values! So I have to set `odds` and all values of `result` to something to have this fixed! The working JSON is: 

```
{
  "_links": {
    "self": {
      "href": "http://api.football-data.org/v1/fixtures/165069"
    },
    "competition": {
      "href": "http://api.football-data.org/v1/competitions/467"
    },
    "homeTeam": {
      "href": "http://api.football-data.org/v1/teams/808"
    },
    "awayTeam": {
      "href": "http://api.football-data.org/v1/teams/801"
    }
  },
  "date": "2018-06-14T15:00:00Z",
  "status": "TIMED",
  "matchday": 1,
  "homeTeamName": "Russia",
  "awayTeamName": "Saudi Arabia",
  "result": {
    "goalsHomeTeam": "null",
    "goalsAwayTeam": "null"
  },
  "odds": "null"
}

```