PDO insert array - php

Question

Reccently I have been attempting to insert an array into a database, I keep getting the error message "Notice: Array to string conversion", I not really sure how to resolve this issue, any advice would be greatly appreciated
<?php
try{
$db = new PDO("mysql:host=localhost;dbname=test", 'root', '');
$db ->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e){
echo $e->getMessage();
die();
}
if ($_SERVER["REQUEST_METHOD"] == "POST"){
$sort = $_POST['sort'];
$count = $_POST["count"];
$error = $_POST["error"];
$audit = array( ':sort' => $sort,
':count' => $count,
':error' => $error
);
foreach($audit as $completeAudit => $display) {
//print_r($display);
$sql = implode("INSERT INTO `audits` (`sort`, `count`, `error`, `timeentered`) VALUES ('$sort','$count','$error', NOW())");
}
$query = $db->prepare($sql);
$query->execute(array(
':sort' => $sort,
':count' => $count,
':error' => $error
));
}
EDIT
$db = new PDO("mysql:host=localhost;dbname=test", 'root', '');
$db ->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
if ($_SERVER["REQUEST_METHOD"] == "POST"){
$sql = "INSERT INTO `audits` (`sort`, `count`, `error`, `timeentered`) VALUES (?,?,?, NOW())";
$stmt = $db->prepare($sql);
$query->execute(array($_POST['sort'], $_POST["count"], $_POST["error"]));
}
This is how it looks now, I deleted everything and used code supplied below

Answer 1

The problem is probably with the implode() call. It requires an array as parameter but you're passing a string.
However, you're overriding the $sql variable in every iteration inside the loop so I'm not sure what it's supposed to do.
Last thing, your code is subject to SQL inejctions so have a look at using prepared statements.

Answer 2

this error has nothing to do with PDO - it's just basic PHP syntax.
However, your PDO is wrong as well. Here is the proper code:
$db = new PDO("mysql:host=localhost;dbname=test", 'root', '');
$db ->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
if ($_SERVER["REQUEST_METHOD"] == "POST"){
$sql = "INSERT INTO `audits` (`sort`, `count`, `error`, `timeentered`) VALUES (?,?,?, NOW())");
$stmt = $db->prepare($sql);
$stmt->execute(array($_POST['sort'], $_POST["count"], $_POST["error"]));
}