INET_NTOA

mysql> select id,inet_ntoa(ip_number) from ip_addresses;
+------+----------------------+
| id   | inet_ntoa(ip_number) |
+------+----------------------+
| 4611 | 10.10.0.3              | 
+------+----------------------+
1 row in set (0.00 sec)

逆は
INET_ATON

mysql> select INET_ATON('10.10.0.3');
+------------------------+
| INET_ATON('10.10.0.3') |
+------------------------+
|              168427523 | 
+------------------------+
1 row in set (0.08 sec)