Add element and key to array php - php

Question

I'm trying to add an element to array, but I get a weird output. The code is the following:
$getalltokens = $db->query("SELECT * FROM Tables WHERE available = '$comp'");
while ($row = $getalltokens->fetch(PDO::FETCH_ASSOC))
{
$fid = $row['FID'];
$tok = $row['token'];
$sql = $db->query("SELECT Firstname,Lastname FROM Users WHERE Token = '$tok'");
$rez = $sql->fetch(PDO::FETCH_ASSOC);
$names[] = $rez;
$fidzy = array(
'FID' => $fid
);
array_push($names, $fidzy);
}
$getalltokens = $db->query("SELECT FID FROM Tables WHERE available = '$comp'");
$tokenz = $getalltokens->fetchAll(PDO::FETCH_ASSOC);
echo json_encode($names);
And the output I get is:
[{"Firstname":"Test","Lastname":"Test"},{"FID":"5"},
{"Firstname":"Test2","Lastname":"Test2"},{"FID":"4"}]
While what I need is the FID to be inside the $names array, so it would be more like:
[{"Firstname":"Test","Lastname":"Test","FID":"5"}]

Answer 1

$rez['FID'] = $fid; /* Added */
$names[] = $rez;
/* $fidzy and array_push removed */

Answer 2

You can use instead of array_push() like
$arrayname[indexname] = $value;
if you use array_push()
<?php
$array[] = $var;
?>
Note: If you use `array_push()` to add one element to the array it's
better to use$array[] = because in that way there is no overhead of
calling a function.
Note: `array_push()` will raise a warning if the first argument is not an array. This differs from the `$var[]` behavior where a new array
is created.
Reference Array push

Answer 3

The solution to the specific problem at hand is selecting all the necessary data in a single query, removing the need to add elements to any array. This is done in the following fashion:
$sql = $db->query("SELECT
Users.Firstname,Users.Lastname,Tables.FID
FROM Users,Tables
WHERE Users.Token = Tables.token");
$rez = $sql->fetchAll(PDO::FETCH_ASSOC);
echo json_encode($rez);