Update successfully but couldn't update into DB - php

Question

I couldn't find any error. I tried the query on phpmyadmin and it works well but when I do in php page, it couldn't update into DB. The following code below:
$registerID = ($_POST['registerID']);
$firstName = ucwords(htmlspecialchars($_POST['firstName']));
$lastName = ucwords(htmlspecialchars($_POST['lastName']));
$emailAddress = htmlspecialchars($_POST['emailAddress']);
$mainAddress = ucwords(htmlspecialchars($_POST['fullAddress']));
$updateCity = ucwords($_POST['userCity']);
$updateCountry = $_POST['userCountry'];
$postalCode = strtoupper(htmlspecialchars($_POST['userZip']));
$profilePic = $_POST['pic'];
$updateProf = " UPDATE register_user
SET firstName='$firstName',
lastName='$lastName',
emailAddress='$emailAddress',
mainAddress='$mainAddress',
registerCity='$updateCity',
registerCountry='$updateCountry',
postalCode='$postalCode'
WHERE registerID = '$registerID'";
if (mysqli_query($mysqli, $updateProf)) {
echo "Record updated successfully";
} else {
echo "Error updating record: " . mysqli_error($mysqli);
}
In the end, there are no errors after I updated on the webpage, it just show Record updated successfully. But it didn't update into DB. Any ideas?
UPDATED CODING
$checkProfile = "SELECT * FROM register_user where emailAddress = '$emailAddress'";
$editProfile = mysqli_query($mysqli,$checkProfile);
if ($editProfile) {
if (mysqli_num_rows($editProfile) > 0) {
header("Location: event?error=That name of email has already been taken");
} else {
$updateQuery = "UPDATE register_user
SET firstName = '$firstName',
lastName = '$lastName',
emailAddress = '$emailAddress',
mainAddress = '$mainAddress',
registerCity = '$updateCity',
registerCountry = '$updateCountry',
postalCode = '$postalCode'
WHERE registerID = '$registerID'";
$updateResult = mysqli_query($mysqli,$updateQuery);
header("Location: profileUser");
}
}
After I updated, it still doesn't work after I am using prepared statement. Any ideas?

Answer 1

Try executing the query first, saving it into a variable.
then, check if the query executed by doing:
if(!$query) echo "Query error : " . $mysqli->error;
This will give you more detailed error report.