PHP Validation

if (isset($_GET["name"]) && isset($_GET["category"])) {
    $query_str = "SELECT id, name, imageurl, price, rating FROM products_mukena WHERE name LIKE %".$_GET["name"]." AND category=".$_GET["category"];
} else if (isset($_GET['name']) && !isset($_GET["category"])) {
    $query_str = "SELECT id, name, imageurl, price, rating FROM products_mukena WHERE name LIKE %".$_GET["name"];
} else if (isset($_GET['category']) && !isset($_GET["name"])) {
    $query_str = "SELECT id, name, imageurl, price, rating FROM products_mukena WHERE category=".$_GET["category"];
}