PHP生成不正确的json

Question

I'm trying to get a json from mysql to use it for creating a tree view with help of bootstrap treeview ajax. But my php produces the wrong json.

I can't understand where do {"1": also "2" "6" and "7" comes from, since I don't have them in my table.

PHP

<?php
//fetch.php
$connect = mysqli_connect("hostname", "user", "", "dbname");
$query = "SELECT * FROM vtiger_customers";
$result = mysqli_query($connect, $query);
//$output = array();
while($row = mysqli_fetch_array($result))
{
  $sub_data["id"] = $row["customersid"];
  $sub_data["customer_name"] = $row["customer_name"];
  $sub_data["type"] = $row["type"];
if ($row["society"]=='')
  $sub_data["parent_id"] = "0";
else $sub_data["parent_id"] = $row["society"];
  $data[] = $sub_data;
}
foreach($data as $key => &$value)
{
$output[$value["id"]] = &$value;
}
foreach($data as $key => &$value)
{
if($value["parent_id"] && isset($output[$value["parent_id"]]))
  {
  $output[$value["parent_id"]]["nodes"][] = &$value;
  }
}
foreach($data as $key => &$value)
{
if($value["parent_id"] && isset($output[$value["parent_id"]]))
  {
  unset($data[$key]);
  }
}
echo json_encode($data);
?>   

JSON output that i get

  {"1":{"id":"78","customer_name":"Holding_1","type":"EPC","parent_id":"","nodes":    [{"id":"77","customer_name":"Ship owner","type":"Shipowner","parent_id":"78"}]},"2":{"id":"79","customer_name":"Holding_2","type":"EPC","parent_id":"","nodes":[{"id":"80","customer_name":"Ship owner 2","type":"Shipowner","parent_id":"79","nodes":[{"id":"82","customer_name":"Sub Ship owner","type":"Shipowner","parent_id":"80"}]},{"id":"81","customer_name":"Ship owner 1","type":"Shipowner","parent_id":"79"}]},"6":{"id":"83","customer_name":"Ship owner","type":"Shipowner","parent_id":""},"7":{"id":"84","customer_name":"Shipyard","type":"Shipyard","parent_id":""}}

JSON format which i need

[{"id":"78","customer_name":"Holding_1","type":"EPC","parent_id":"","nodes":    [{"id":"77","customer_name":"Ship owner","type":"Shipowner","parent_id":"78"}]},{"id":"79","customer_name":"Holding_2","type":"EPC","parent_id":"","nodes":[{"id":"80","customer_name":"Ship owner 2","type":"Shipowner","parent_id":"79","nodes":[{"id":"82","customer_name":"Sub Ship owner","type":"Shipowner","parent_id":"80"}]},{"id":"81","customer_name":"Ship owner 1","type":"Shipowner","parent_id":"79"}]},{"id":"83","customer_name":"Ship owner","type":"Shipowner","parent_id":""},{"id":"84","customer_name":"Shipyard","type":"Shipyard","parent_id":""}]

MySQL Table

customers_id  customers_number society   type       customer_name
    78          46546                    EPC          Holding_1 
    79          53456                    EPC          Holding_2 
    83          763645                   Shipowner    Ship owner 
    77          324543            78     Shipowner    Ship owner 
    84          63465435                 Shipyard     Shipyard 
    80          534523            79     Shipowner    Ship owner 
    81          836754            79     Shipowner    Ship owner 
    82          8746546           80     Shipowner    Sub Ship owner 

Answer 1

The initial $data array is an indexed array. To each key is assigned an item array. Each item array has the key parent_id and a value >= 0...

...The 1, 2, 6 and 7 are the indexes in the initial $data array, at which the value for the parent_id key of the corresponding item array is 0.

In order to obtain what you need, you have to reset the array indexes of $data before printing it as json-encoded string:

//...

$data = array_values($data);

echo json_encode($data);