Warning: mysqli_stmt::bind_param(): Number of variables doesn't match number - php

Question

I am receiving this error and am unable to figure out why.
Warning: mysqli_stmt::bind_param(): Number of variables doesn't match number of parameters in prepared statement in C:\xampp\htdocs\insert.php on line 32
$SELECT = "SELECT id FROM heroes WHERE name = ? LIMIT 1";
$INSERT = "INSERT INTO heroes (id, name, title, bp, ticket, diamond) VALUES ('NULL', '$name', '$title', '$bp', '$ticket', '$diamond')";
//Prepare statement
$stmt = $connection->prepare($SELECT);
$stmt->bind_param("s", $name);
$stmt->execute();
$stmt->bind_result($name);
$stmt->store_result();
$rnum = $stmt->num_rows;
if ($rnum==0){
$stmt->close();
$stmt = $connection->prepare($INSERT);
$stmt->bind_param("sssss", $name, $title, $bp, $ticket, $diamond);
$stmt->execute();
echo "New hero inserted successfully, sir!";
} else {
echo "There is already a hero with this name, sir!";
}
$stmt->close();
$connection->close();

Answer 1

You don't actually have any params to bind in your insert:
$INSERT = "INSERT INTO heroes (id, name, title, bp, ticket, diamond) VALUES ('NULL', '$name', '$title', '$bp', '$ticket', '$diamond')";
Do this:
$INSERT = "INSERT INTO heroes (name, title, bp, ticket, diamond) VALUES (?, ?, ?, ?, ?)";
Then the values you bind replace the question marks.
Also note there is a very significant difference between NULL and 'NULL' -- the latter is a string. If you have an auto-incrementing ID field, just leave it out of the insert and the database will fill it in for you.