Username check comes back as username already exist when it doesnt - php

Question

I have a code that checks if a username exists or not, but when I run the code and enter in a username i inserted into my database using phpmyadmin it says the username dosent exist, am wondering where i went wrong?
here is my php code:
<?php
require_once 'connect.php';
$conn = dbConnect();
if (isset($_POST['username']))
{
$sql = $conn->prepare("SELECT COUNT(id)
FROM users
WHERE username = :username");
$sql->execute(array(":username" => $_POST['username']));
$rows_number = $sql->fetchColumn();
if($rows_number ==0)
{
echo "Username doesn't exist";
exit;
}
else
{
echo "Username already exists";
exit;
}
}
?>
here is my php connect.php:
<?php
function dbConnect(){
$db = null;
$db_host = "localhost";
$db_username ="user";
$db_pass ="pass";
$db_name = "accounts";
try{
$db = new PDO('mysql:host='.$db_host.';dbname'.$db_name,$db_username,$db_pass);
}
catch (PDOException $e) {
echo '<p>Cannot connect to database !!</p>';
exit;
}
return $db;
}
?>

Answer 1

Seeing as I do not have 50+ rep I can't comment but post your connect.php code and exclude the username and password so I can see if its the connect.php that's giving the problem
Edit: your problem lye's here:
';dbname'.$db_name,$db_username,$db_pass);
it should be
';dbname='
and then append on your variable $db_name. Further explanation is the ';dbname is equal to the value you gave your variable.

Answer 2

You may not have initialized the query statement
/* create a prepared statement */
<?php
$stmt = $mysqli->stmt_init();
if ($stmt->prepare("SELECT District FROM City WHERE Name=?")) {
/* bind parameters for markers */
$stmt->bind_param("s", $city);
/* execute query */
$stmt->execute();
/* bind result variables */
$stmt->bind_result($district);
/* fetch value */
$stmt->fetch();
printf("%s is in district %s\n", $city, $district);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>