string '0' is not equal to null, int 0 is equal to null
$a = null;
$b = "0";
if ($a < $b) {
echo "1";
} else {
echo "2";
}
// 输出1
string '0' is not equal to null, int 0 is equal to null
$a = null;
$b = "0";
if ($a < $b) {
echo "1";
} else {
echo "2";
}
// 输出1