using mysqli prepared stmt within "if" condition with "||" and "&&" operator - php

Question

I am just learning mysqli prepared statements and now i have run into a problem and could not get a way out of it. It is the registration form and takes in "username" "email" and "password". if username and email already exists in the database then it doesnot allow registeration. i've used post method and the code is as,
//validating email
if(!filter_var($user_email, FILTER_VALIDATE_EMAIL) === true) {
echo "invalid email";
exit();
}
//valid email
else{
//prepared query
$query_name = "SELECT * FROM users WHERE user_name = ?";
$query_email = "SELECT * FROM users WHERE user_email = ?";
//prepared statements
$stmt_name = mysqli_prepare($conn, $query_name);
$stmt_email = mysqli_prepare($conn, $query_email);
//if bind failure
if((!mysqli_stmt_bind_param($stmt_name, "s", $user_name)) && (!mysqli_stmt_bind_param($stmt_email, "s", $user_email))){
echo "bind unsuccessfull";
exit();
}
else{
//if execution fails
if( !mysqli_stmt_execute($stmt_name) && !mysqli_stmt_execute($stmt_email)){
echo "stmt execution failed";
exit();
}
//else if execution success
else{
$result_name = mysqli_stmt_store_result($stmt_name);
$result_email = mysqli_stmt_store_result($stmt_email);
//rows
$row_name = mysqli_stmt_num_rows($stmt_name);
$row_email = mysqli_stmt_num_rows($stmt_email);
echo $row_name;
echo $row_email;
}
}
}
it looks like the first part before && in if condition works and the second doesnot work at all. i have tried registering it with existing "email" in the database but the result is still 0.
the connection is fine and works!
Any help will be appreciated>

Answer 1

Instead of doing so much complex code, use single query to do your job
//validating email
if(!filter_var($user_email, FILTER_VALIDATE_EMAIL) === true) {
echo "invalid email";
exit();
}
else{
$stmt = mysqli_prepare($conn, "SELECT * FROM users WHERE user_name = ? OR user_email = ?");
mysqli_stmt_bind_param($stmt, 'ss', $user_name, $user_email);
if( !mysqli_stmt_execute($stmt)){
echo "stmt execution failed";
exit();
}else{
$result_name = mysqli_stmt_store_result($stmt_name);
$result_email = mysqli_stmt_store_result($stmt_email);
//rows
$row_name = mysqli_stmt_num_rows($stmt_name);
$row_email = mysqli_stmt_num_rows($stmt_email);
echo $row_name;
echo $row_email;
}
}

Answer 2

$query_name = "SELECT * FROM users WHERE user_name = ? OR user_email = ?";
you don't need to check the condition twice at same time.If someone will login through email or username then this query will check for both username and email.

Answer 3

I would be tempted to roll both queries together using an or condition in conjunction with a try/catch block so that you can throw exceptions at certain stages if a condition is not met.
if( !isset( $user_email ) or !filter_var( $user_email, FILTER_VALIDATE_EMAIL ) === true ) {
exit("invalid email");
} else {
try{
if( isset( $user_name, $user_email ) ){
$sql='select `user_name`,`user_email` from `users` where `user_name` = ? or user_email = ?'
$stmt=$conn->prepare( $sql );
if( $stmt ){
$stmt->bind_param('ss', $user_name, $user_email );
$result=$stmt->execute();
if( $result ){
$stmt->store_result();
if( $stmt->num_rows == 1 ){
/* user name &/or email already exists */
$stmt->bind_result( $name, $email );
$stmt->fetch();
printf('whoohoo! - found user "%s" with email "%s"', $name, $email );
} else {
/* no record for username or email*/
/* sql query to insert new user */
}
$stmt->free_result();
$stmt->close();
} else {
throw new Exception('sql query failed to return any results');
}
} else {
throw new Exception('unable to prepare sql');
}
} else {
throw new Exception('username &/or email are missing');
}
}catch( Exception $e ){
echo $e->getMessage();
}