Data won't save into MySQL database - php

Question

I can connect to my DB, but nothing saves into it. In the section where it is suppose to save it into the DB, it echos "New User" and the $sql line with the data that should be saved. Can anyone see why this shouldn't be saving my data?
$dbh = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
//$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
if($dbh){
echo "Connected successfully";
}else{
die("Connection failed: " . mysqli_connect_error());
}
if(isset($_SESSION['steamid'])) {
include ('steamauth/userInfo.php');
if (!empty($steamprofile['steamid'])) {
$stmt = $dbh->prepare("SELECT count(*) from user WHERE steam_id = :steam_id");
$stmt->bindValue(':steam_id', $steamprofile['steamid']);
$stmt->execute();
$count = $stmt->fetchColumn();
}
//Row will return false if there was no value
if ($count == 0) {
//insert new data
echo "New user";
$sql = "INSERT INTO user (display_name, user_url, steam_id, profile_image)
VALUES ('$steamprofile[personaname]', '$steamprofile[profileurl]', $steamprofile[steamid], '$steamprofile[avatar]')";
echo($sql);
// die();
} else {
//User exist
echo "User exists";
}
}else{
echo "no user signed in";
}
Table Schema: http://gyazo.com/ef9badc3ae72b73557ed80efe2413ea3

Answer 1

There it goes.
if ($count == 0) {
echo "New user";
$sql = "INSERT INTO user (display_name, user_url, steam_id, profile_image)
VALUES ('$steamprofile[personaname]', '$steamprofile[profileurl]', $steamprofile[steamid], '$steamprofile[avatar]')";
$dbh->query($sql); // You missed that line of code.
echo($sql); // This will only echo out your query, not the result.
} else {
//User exist
echo "User exists";
}

Answer 2

You didn't execute the INSERT sql statement. You can use the following statement after $sql:
$result = mysqli_query($sql);
Make sure you read the $result and do appropriate things, e.g.:
if($result === true) {
// success
} else {
// failed
}

Answer 3

As in your codes the $sql has not been executed, it will print only the variable. Execute it first.

Answer 4

Execute insert query. Try this snippet in your code.
try {
$stmt = $db->prepare($query);
$result = $stmt->execute($query_params);
} catch (PDOException $ex) {
}