As we know that an empty hexadecimal value is a zero-length binary string hence if 0 is added to it then the result would be 0. In other words, we can say that if we convert an empty hexadecimal value to a number then it produces 0. The following query will make it understand −
mysql> SELECT X''+ 0; +--------+ | X''+ 0 | +--------+ | 0 | +--------+ 1 row in set (0.15 sec)