actually tama ito sir.. kasi magiging undefined yung $param_id sa loob ng mysqli_stmt_bind_param($stmt, "i", $param_id); kaya magiging null yung id sa SELECT query which magiging result ng boolean false na return ng mysqli_fetch_array($result, MYSQLI_ASSOC);
Kung front end development lang gusto mo. learn
Basic
HTML5, CSS3, Bootstrap, Javascript,
Advance
Jquery, SASS, JSON, Gulp, Angular, React, (pwede ka din mag aral ng latest na frameworks for javascript)