There is really no way of knowing it.
Let's say the table tbl_numbers(id, value) has rows (1,"one") and (2,"two");
$result1="update tbl_numbers set value='first' where id=1";
Fıkra doğru döner ve mysql_affected_rows eğer $ result1 check if () 1 döndürür.
However, for $result2="update tbl_numbers set value='two' where id=2";
If you check $result2 in if clause it returns true and mysql_affected_rows() returns 0.
And, for $result3="update tbl_numbers set value='three' where id=3";
If you check $result3 in if clause it returns true and mysql_affected_rows() returns 0.