[Exim] Question about sql.

I know, this question a but is off topic in this group. Is more about
mysql than exim but I am posting it anyway since is for use with exim
and I think the answer should be useful for others.

I have an existing table for authorizations who look like this.

mysql> select * from b;
+-------------+------+

| ip          | auth |

+-------------+------+
| 156.24.56.4 | no |
| 156.24.56.% | yes |
+-------------+------+
2 rows in set (0.00 sec)

mysql> select * from b where '156.24.56.9' like ip;
+------+
| auth |
+------+
| yes |
+------+
1 row in set (0.00 sec)

but if the ip address is 156.24.56.4 I got to lines.

mysql> select * from b where '156.24.56.4' like ip;
+------+
| auth |
+------+
| no |
| yes |
+------+
2 rows in set (0.00 sec)

and I am looking for a request to return the authorization for a
specific ip address.


Thanks for any suggestion.

--
Fred -