创建json格式

I created json format from many table by using query(Union).But I get only one json result instead of three results.The result is

["Used","Huawei","Samsung","Mandalay"]

So,I want to insert name in front of "Used" like that ["Condition":"Used"]. How can I do that?

Here is my code

<?php
    $result=mysql_query(" SELECT ttd.name 
                      FROM   `taxonomy_term_data` AS ttd
                      INNER JOIN `field_data_field_ph_condition` AS fdc
                      ON   fdc.field_ph_condition_tid=ttd.tid
                      INNER JOIN `node` AS N
                      ON n.nid=fdc.entity_id 
                      UNION
                      SELECT ttd.name 
                      FROM   `taxonomy_term_data` AS ttd
                      INNER JOIN `field_data_field_brand` AS fb
                      ON   fb.field_brand_tid=ttd.tid
                      INNER JOIN `node` AS N
                      ON n.nid=fb.entity_id 
                      UNION
                      SELECT ttd.name 
                      FROM   `taxonomy_term_data` AS ttd
                      INNER JOIN `field_data_field_city` AS fb
                      ON   fb.field_city_tid=ttd.tid
                      INNER JOIN `node` AS N
                      ON n.nid=fb.entity_id 
                      ") or die(mysql_error());

 while ($row = mysql_fetch_array( $result, MYSQL_ASSOC)) {
 $json_response[] = $row['name'];
}
  echo json_encode($json_response); 
?>