将php数组转换为单个JSON对象

Question

I am having an issue with how I am converting my php array into a JSON object. No matter what I try, I either print everything out as multiple objects or it comes out as null.Wrapping it in pre tags, here is the closest that I got it:

My code:

$content = mysqli_query($dbcon, 
  "SELECT title, last_name AS lastname
   FROM revision, field_last_name
   WHERE vid = entity_id;"
);

echo "<pre>";
while($row = mysqli_fetch_array($content))
{
  print json_encode($row);
  print '<br/>';
}
echo "</pre>";

My output:

{"0":"John Apple","title":"John Apple","1":"Apple","lastname":"Apple"}
{"0":"Kumar Patel","title":"Kumar Patel","1":"Patel","lastname":"Patel"}
{"0":"Michaela Quinn","title":"Michaela Quinn","1":"Quinn","lastname":"Quinn"}
{"0":"Peyton Manning","title":"Peyton Manning, MD","1":"Manning","lastname":"Manning"}
{"0":"John Doe","title":"John Doe","1":"Doe","lastname":"Doe"}
{"0":"Jane Lee","title":"Jane Lee","1":"Lee","lastname":"Lee"}
{"0":"Dan McMan","title":"Dan McMan","1":"McMan","lastname":"McMan"}
{"0":"Yu Win","title":"Yu Win","1":"Win","lastname":"Win"}

My two questions are:

1) Why is there a "0":"John Apple" and a "1":"Apple" when all I want is "title":"John Apple" and "lastname":"Apple" in my object?

2) Why is everything displaying as multiple objects?

Thanks!

---EDIT---

$arr = array()

echo "<pre>";   

while($row = mysqli_fetch_assoc($content))
{     
  $arr[] = $row;
}

print $arr;
echo "</pre>";

Answer 1

field_last_name is your table name? can you distinguish each column name prefix by table name like revision.title in your query and get all data in a single array and then json_encode it?

   $content = mysqli_query($dbcon, 
      "SELECT title, last_name AS lastname
       FROM revision, field_last_name
       WHERE vid = entity_id;"
    );
    $arr = array();

    echo "<pre>";
    while($row = mysqli_fetch_assoc($content))
    {
      $arr[] = $row;
    }
      print_r(json_encode($arr));


    echo "</pre>";