MySql General error: 2053 - php

Question

I'm getting the error:
ERROR: SQLSTATE[HY000]: General error: 2053
I have no idea why this is happening because the code works fine and the database is updated, but it still returns this error.
Here's my code:
<?php
header("Content-Type: application/json; charset=UTF-8");
require 'UHCauth.php';
try {
$conn = new PDO("mysql:host=$mysql_serv;dbname=$mysql_db", $mysql_user, $mysql_pass);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$conn->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
if(isset($_GET['d6518e47'])) {
$USERNAME = $_GET['d6518e47'];
$stmt = $conn->prepare(
"UPDATE $mysql_table
SET KILLS = KILLS+1 WHERE USERNAME = :USERNAME"
);
$stmt->execute(array('USERNAME' => $USERNAME));
$row = $stmt->fetch(PDO::FETCH_ASSOC);
echo json_encode($row);
} else {
$stmt = $conn->prepare(
"SELECT * FROM $mysql_table
ORDER BY
McVersion DESC,
ModVersion DESC
LIMIT 1"
);
$stmt->execute();
$row = $stmt->fetch(PDO::FETCH_ASSOC);
echo json_encode($row);
}
} catch(PDOException $e) {
echo 'ERROR: ' . $e->getMessage();
}
?>

Answer 1

$row = $stmt->fetch(PDO::FETCH_ASSOC); is the line that will cause your error.
Why?
Because there's nothing to fetch - in array - after an update
Remember that
PDO::FETCH_ASSOC: returns an array indexed by column name as returned
in your result set
So, no result set ... no party
If you want to know exit status of your command, just use the return value of execute() function
$rv = $stmt->execute(array('USERNAME' => $USERNAME));