PHP invalid JSON encoding - php

Question

I'm trying to GET a JSON format back when I POST a specific ID to my database. As I get more than one result I have multiple rows, which I want to get back. I do get different arrays back, but it is not a valid JSON Format. Instead of
[{...},{...},{...}]
it comes back as
{...}{...}{...}
Therefore the [...] are missing and the arrays are not separated by commas.
My code is down below. The function "getUserBookingsKl" is defined in a different php.
//get user bookings
public function getUserBookingsKl($id) {
//sql command
$sql = "SELECT * FROM `***` WHERE `hf_id`=$id AND `alloc_to`>DATE(NOW()) AND NOT `confirmation`=0000-00-00 ORDER BY `alloc_from`";
//assign result we got from $sql to $result var
$result = $this->conn->query($sql);
// at least one result
if ($result !=null && (mysqli_num_rows($result) >= 1 ))
{
while ($row = $result->fetch_array())
{
$returArray[] = $row;
}
}
return $returArray;
}
...
...
foreach($userdb as $dataset)
{
$returnArray["group"] = $dataset["kf_id"];
$returnArray["from"] = $dataset["alloc_from"];
$returnArray["to"] = $dataset["alloc_to"];
echo json_encode($returnArray);
# return;
}
// Close connection after registration
$access->disconnect();

Answer 1

It looks like you're sequentially emitting the values, not pushing into an array. You need to make an array, push into it, then call json_encode on the resulting structure:
$final = [ ];
foreach ($userdb as $dataset)
{
$returnArray = [ ];
$returnArray["group"] = $dataset["kf_id"];
$returnArray["from"] = $dataset["alloc_from"];
$returnArray["to"] = $dataset["alloc_to"];
$final[] = $returnArray;
}
echo json_encode($final);
Note that it's important here to not use the same variable inside the loop each time through or you're just pushing the same array in multiple times.