pass php mysql result to json array

Sometimes you need to pass the mysql result into json array inorder to fetch the output in json defined format. In that scenario, use the following concept,

$getData=mysql_query("Your Mysql Query");
$jsonArr = array(); // declare array 
while ($result = mysql_fetch_array($getData)) 
{ 
  $fetchRow = array($result['fieldName']);
  array_push($jsonArr,$fetchRow);
} 
echo json_encode($jsonArr);
this code will give you result in the format,
[["val1"],["val2"],["val3"]]