MS Access SQL query for IP address range - sql

Question

IP addresses are being stored as text values in an Access database in the format 192.168.0.1 - 192.168.0.254 in a junction table.
Junction table e.g Areas
Name IPAddress
Area1 192.168.0.1 - 192.168.0.254
Area2 192.168.1.1 - 192.168.1.254
I need to be able to search for records that between these ranges e.g.
SELECT * FROM devices WHERE ipaddress = 192.168.0.1 /Returns record Name1
or
SELECT * FROM tablename WHERE ipaddress BETWEEN 192.168.0.1 AND 192.168.0.25 /Returns record Name1,Name2,Name3,etc

Answer 1

A successful approach would be composed of three parts:
Parse the IPAddress column and split it up into two logical (text) columns: IPAddressLow and IPAddressHigh that capture the range of IPs for an area. Let's call this qryAreas:
select
[Name]
, ... as IPAddressLow
, ... as IPAddressHigh
from Areas
Implement a function (in VBA which you can then call from within Access SQL) to do comparisons on IP addresses. The comparator function could be something like:
' Returns:
' -1 if IP1 < IP2
' 0 if IP1 = IP2
' 1 if IP1 > IP2
Function CompareIPAddresses(ip1 As String, ip2 As String) As Integer
ip1_arr = Split(ip1, ".")
ip2_arr = Split(ip2, ".")
For i = 0 To 3
ip1_arr(i) = CLng(ip1_arr(i))
ip2_arr(i) = CLng(ip2_arr(i))
Next i
If ip1 = ip2 Then
retval = 0
ElseIf ip1_arr(0) < ip2_arr(0) Then
retval = -1
ElseIf ip1_arr(0) = ip2_arr(0) And ip1_arr(1) < ip2_arr(1) Then
retval = -1
ElseIf ip1_arr(0) = ip2_arr(0) And ip1_arr(1) = ip2_arr(1) And ip1_arr(2) < ip2_arr(2) Then
retval = -1
ElseIf ip1_arr(0) = ip2_arr(0) And ip1_arr(1) = ip2_arr(1) And ip1_arr(2) = ip2_arr(2) And ip1_arr(3) < ip2_arr(3) Then
retval = -1
Else
retval = 1
End If
CompareIPAddresses = retval
End Function
Use the above function in queries to figure out if an IP address is equal to a certain value or falls within a certain range. E.g., if you have an address 192.168.1.100 and want to find out which area it's in, you can do:
select [Name]
from qryAreas
where CompareIPAddresses(IPAddressLow, '192.168.1.100') in (-1, 0)
and CompareIPAddresses('192.168.1.100', IPAddressHigh) in (-1, 0)
The where clause here is the clunkier equivalent of the more elegant where 192.168.1.100 between IPAddressLow and IPAddressHigh syntax, because you don't have a native IP address data type and its corresponding operators--so you're rolling your own.

Answer 2

For searching on a range of IP addresses you might be able to use a little VBA function like this
Option Compare Database
Option Explicit
Public Function ZeroPaddedIP(IP As String) As String
Dim rtn As String, octets() As String, octet As Variant
rtn = ""
octets = Split(IP, ".")
For Each octet In octets
rtn = rtn & "." & Format(Val(octet), "000")
Next
ZeroPaddedIP = Mid(rtn, 2) ' trim leading "."
End Function
It pads the octets with leading zeros so
ZeroPaddedIP("192.168.0.1") --> "192.168.000.001"
and your query could do something like
SELECT * FROM tablename
WHERE ZeroPaddedIP(ipaddress) BETWEEN "192.168.000.001" AND "192.168.000.025"
That query will do a table scan because it cannot use any existing index on [ipaddress]. If performance is an issue, you might consider storing your IP addresses in padded form (either instead of, or in addition to the normal un-padded format).
Edit
For a test table named [NetworkData] ...
ID IP Description
-- ------------- -----------
1 192.168.0.1 router
2 192.168.0.2 test server
3 192.168.0.3 dev server
4 192.168.0.102 test client
5 192.168.0.103 dev client
... the VBA function shown above could be used in an Access query like this ...
SELECT
IP,
ZeroPaddedIP(IP) AS PaddedIP
FROM NetworkData
... to produce the following results ...
IP PaddedIP
------------- ---------------
192.168.0.1 192.168.000.001
192.168.0.2 192.168.000.002
192.168.0.3 192.168.000.003
192.168.0.102 192.168.000.102
192.168.0.103 192.168.000.103
... but only if the query is executed from within Access itself. The same results could be obtained from the following query, but this one will work if the query is run against the Access database from some other application (like Excel):
SELECT
IP,
Right('000' & Octet1, 3) & '.' & Right('000' & Octet2, 3) & '.' & Right('000' & Octet3, 3) & '.' & Right('000' & Octet4, 3) AS PaddedIP
FROM
(
SELECT
IP,
Octet1,
Octet2,
Left(TheRest2, InStr(TheRest2, '.') - 1) AS Octet3,
Mid(TheRest2, InStr(TheRest2, '.') + 1) AS Octet4
FROM
(
SELECT
IP,
Octet1,
Left(TheRest1, InStr(TheRest1, '.') - 1) AS Octet2,
Mid(TheRest1, InStr(TheRest1, '.') + 1) AS theRest2
FROM
(
SELECT
IP,
Left(IP, InStr(IP, '.') - 1) AS Octet1,
Mid(IP, InStr(IP, '.') + 1) AS theRest1
FROM NetworkData
) AS q1
) AS q2
) AS q3
So, if you were querying the data from Excel (or wherever) and you tried to use
SELECT * FROM NetworkData
WHERE IP Between '192.168.0.1' And '192.168.0.25'
you would get the following incorrect result
ID IP Description
-- ------------- -----------
1 192.168.0.1 router
2 192.168.0.2 test server
4 192.168.0.102 test client
5 192.168.0.103 dev client
whereas if you used
SELECT NetworkData.*
FROM
NetworkData
INNER JOIN
(
SELECT
IP,
Right('000' & Octet1, 3) & '.' & Right('000' & Octet2, 3) & '.' & Right('000' & Octet3, 3) & '.' & Right('000' & Octet4, 3) AS PaddedIP
FROM
(
SELECT
IP,
Octet1,
Octet2,
Left(TheRest2, InStr(TheRest2, '.') - 1) AS Octet3,
Mid(TheRest2, InStr(TheRest2, '.') + 1) AS Octet4
FROM
(
SELECT
IP,
Octet1,
Left(TheRest1, InStr(TheRest1, '.') - 1) AS Octet2,
Mid(TheRest1, InStr(TheRest1, '.') + 1) AS theRest2
FROM
(
SELECT
IP,
Left(IP, InStr(IP, '.') - 1) AS Octet1,
Mid(IP, InStr(IP, '.') + 1) AS theRest1
FROM NetworkData
) AS q1
) AS q2
) AS q3
) AS q4
ON q4.IP = NetworkData.IP
WHERE q4.PaddedIP Between '192.168.000.001' And '192.168.000.025'
you would receive the following correct result
ID IP Description
-- ----------- -----------
1 192.168.0.1 router
2 192.168.0.2 test server
3 192.168.0.3 dev server