And with some error checking

alter function dbo.ConvertIp2Num(@ip varchar(15))

returns bigint

as

begin

returncase

when @ip like '%[^0-9.]%' then NULL

when @ip like '%.%.%.%.%' then null

when @ip like '%..%' then null

when @ip like '%[0-9][0-9][0-9][0-9]%' then null

else 16777216.0 * parsename(@ip, 4)

+ 65536 * parsename(@ip, 3)

+ 256 * parsename(@ip, 2)

+ 1 * parsename(@ip, 1)

end

end

Or see this topic from 2006

http://www.sqlservercentral.com/Forums/Topic302100-145-1.aspx