PHP that returns null table fields that are neither empty nor null in MySQL

I solved using json_encode (utf8ize ($ row));

Here is the complete new PHP:

   $rest_api = array();
function utf8ize($d) {
    if (is_array($d)) {
        foreach ($d as $k => $v) {
            $d[$k] = utf8ize($v);
        }
    } else if (is_string ($d)) {
        return utf8_encode($d);
    }
    return $d;
}

/** connect to mysql **/
$mysql = new mysqli($config["host"], $config["user"], $config["pass"], $config["dbase"]);
if (mysqli_connect_errno()){
    die(mysqli_connect_error());
}


$query="SELECT nome FROM formas_pagamento ORDER BY cod_forma_pagamento ASC";

$result = $mysql->query($query);
//$result=$con->query($query);



if ($result->num_rows > 0) 
{
    $count=0;
    echo "[";
    while($row = $result->fetch_assoc()) 
    {
            $count++;

            echo json_encode(utf8ize($row));

            if($count!=$row_cnt)
            {
                    echo ",";
            }


    }
    echo "]";
}
else
{
echo "error";
}

?>

There are functions that already associate the results, you do not have to go through it manually and reinvent the wheel, at the risk of creating errors. Use the mysqli_fetch_all function:

$query = "SELECT nome FROM formas_pagamento ORDER BY cod_forma_pagamento ASC";

$result = $con->query($query);

$resultArray = $result->fetch_all(MYSQLI_ASSOC);

echo json_encode($resultArray);

Why complicate and "invite" mistakes? There is a much easier way to do this (untested code):

$output = [];
while($row = $result->fetch_assoc()) 
{
  $output[] = $row;
}
echo json_encode($output);

You can do in a more simplified way that will work perfectly:

$query="SELECT
   nome
FROM
   formas_pagamento
ORDER BY
   cod_forma_pagamento ASC";

$arr = [];
foreach ($con->query($query, PDO::FETCH_ASSOC) as $row) {
    $arr[] = $row;
}

echo json_encode($arr);

If you have any questions, please visit link

json_encode requires UTF-8, this is probably already the format of your bank, but you may not have specified this in the connection, as I explain in this answer:

• link

If it's OOP:

$mysqli = new mysqli('HOST', 'usuario', 'senha', 'banco');

if ($mysqli->connect_error) {
    printf('Erro de conexão: %s', $mysqli->connect_errno);
    exit;
}

/*
 * compatibilidade para to 5.2.9 e 5.3.0.
 */
if (mysqli_connect_error()) {
    printf('Erro de conexão: %s', mysqli_connect_error());
    exit;
}

//Define para UTF-8
if (false === $mysqli->set_charset('utf8')) {
    printf('Error ao usar utf8: %s', $mysqli->error);
    exit;
}

With procedural mysqli:

<?php
$link = mysqli_connect('HOST', 'usuario', 'senha', 'banco');

if (mysqli_connect_error()) {
    printf('Erro de conexão: %s', mysqli_connect_error());
    exit;
}

//Define para UTF-8
if (!mysqli_set_charset($link, 'utf8')) {
    printf('Error ao usar utf8: %s', mysqli_error($link));
    exit;
}

It is not necessary to use utf8_encode in a recursive way, as you did in your answer, just understand what UTF-8 is and know how to apply it, the answer that I linkei shows step by step.