Ternary expression containing loose comparison in else branch yields unexpected result

Question

Could someone help me with this code? On my website, there is no result.

<?php
if (isset($_GET['id']) ? $product['valid2'] : ''==1) {
    echo "Yes";
} elseif (isset($_GET['id']) ? $product['valid2'] : ''==0) {
    echo "No";
}

Answer 1

I solved it with this function:

<?php
          
$v2 = isset($_GET['id']) ? $product['valid2'] : '';          
 
          
if ($v2==1) {
    echo "Yes";
} elseif ($v2==0) {
    echo "No";
}

?> 

Thanks for all answers!