Question

I have the following table

Table bots{
    ip_address varchar(15),
    bot_name varchar(32)
}

Given that some bots have static ips and others won’t, the table has entries such as 192.168.0 and 192.168.1.15

Now I have to see if a given ip belongs to a bot. I was thinking something along these lines

SELECT bot_name
FROM bots
WHERE __input_ip__  REGEXP '^ip_address'

but this won’t work for the obvious reason that it is looking for a string that starts with ip_address.

So my question is, how can I include a field name within a sql regular expression ?

Answer 1

You might want to consider storing the IP address as an INT UNSIGNED. Also store the netmask so you can tell the difference between a static address and a subnet.

INSERT INTO bots (ipaddress, netmask, bot_name) 
VALUES (INET_ATOI('192.168.1.0'), INET_ATOI('255.255.255.0'), 'Wall-E');

Then you can query to see if an input IP address matches:

SELECT bot_name
FROM bots
WHERE __input_ip__ & netmask = ipaddress & netmask;

Using integers for IP addresses instead of CHAR(15) is a common optimization. Even storing the 8 bytes for the IP address and the netmask is little more than half the storage of the CHAR(15). And the bitwise operations are likely to be a lot faster than the regular expression matching, and it’s easier to avoid the corner cases like in @Gumbo’s comment.