Why do I get this function call error on an non-object when I am calling a function on an object?

Question

Error:

Fatal error: Call to a member function bind_param() on a non-object in /var/www/web55/web/pdftest/events.php on line 76

Co

Answer 1

AND c.category_id = ? - there is no table alias c in your query.

Besides that try

$stmt = $this->link->prepare($sql);
if (!$stmt) {
  throw new ErrorException($this->link->error, $this->link->errno);
}

if (!$stmt->bind_param('i', $this->locationID) || !$stmt->execute()) {
  throw new ErrorException($stmt->error, $stmt->errno);
}