I'm trying to mesh the below mysql query results into a single json object, but not quite sure how to do it properly.

//return data
$sql_result = mysql_query($sql,$connection) or die ("Fail.");
$arr = array();
while($obj = mysql_fetch_object($sql_result)) { $arr[] = $obj; }
echo json_encode($arr); //return json

//plus the selected options
$sql_result2 = mysql_query($sql2,$connection) or die ("Fail.");
$arr2 = array();
while($obj2 = mysql_fetch_object($sql_result2)) { $arr2[] = $obj2; }
echo json_encode($arr2); //return json

Here's the current result:

[{"po_number":"test","start_date":"1261116000","end_date":"1262239200","description":"test","taa_required":"0","account_overdue":"1","jobs_id":null,"job_number":null,"companies_id":"4","companies_name":"Primacore Inc."}][{"types_id":"37"},{"types_id":"4"}]

Notice how the last section [{"types_id":"37"},{"types_id":"4"}] is placed into a separate chunk under root. I'm wanting it to be nested inside the first branch under a name like, "types".

I think my question has more to do with Php array manipulation, but I'm not the best with that.

Thank you for any guidance.