在數據庫設計時，爲了查詢效率，常常把點分十進制表示的ip地址設計爲bigint類型。存儲的時候，怎麼把點分十進制轉換爲bigint，請參考下面的sql自定義函數：
USE [temp]
GO
/****** 對象: UserDefinedFunction [dbo].[UF_CovertIPToInt] 腳本日期: 08/06/2012 16:55:22 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author: ----
-- Create date: 2009-05-11
-- Description: 轉換ip
-- =============================================
CREATE FUNCTION [dbo].[UF_CovertIPToInt]
(
@ip varchar(20)
)
RETURNS bigint
AS
BEGIN
declare @pos int
declare @sub1 varchar(10)
declare @sub2 varchar(10)
declare @sub3 varchar(10)
declare @sub4 varchar(10)
set @pos = charindex('.',@ip)
if(@pos<1) return 0
set @sub1 = substring(@ip,0,@pos)
--select @sub1
set @ip = substring(@ip, @pos+1 ,len(@ip) - @pos + 1)
--select @ip
set @pos = charindex('.',@ip)
if(@pos<1) return 0
set @sub2 = substring(@ip,0,@pos)
--select @sub2
set @ip = substring(@ip, @pos+1 ,len(@ip) - @pos + 1)
--select @ip
set @pos = charindex('.',@ip)
if(@pos<1) return 0
set @sub3 = substring(@ip,0,@pos)
--select @sub3
set @ip = substring(@ip, @pos+1 ,len(@ip) - @pos + 1)
if(len(@ip)<1) return 0
select @sub4 = @ip
--select @sub4
return cast(@sub1 as bigint ) * 16777216 + cast(@sub2 as bigint ) * 65536 + cast(@sub3 as bigint )*256 + cast(@sub4 as bigint )
END
有了上面的函數，我可以方便地進行轉換，例如：
select dbo.UF_CovertIPToInt('192.168.1.100') as ip
顯示的時候，爲了方便閱讀，常常需要把bigint轉換爲點分十進制，請參考下面的自定義函數：
USE [temp]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE FUNCTION [dbo].[UF_ConvertIPToStr]
(
@ip bigint
)
RETURNS varchar(20)
AS
BEGIN
RETURN cast((@ip/16777216)% 256 as varchar(4)) + '.' + cast( (@ip/65536)% 256 as varchar(4)) +'.'+ cast( (@ip/256)%256 as varchar(4))+ '.'+ cast( (@ip%256)as varchar(4))
END
可以通過下面的方式調用該函數：
select dbo.UF_ConvertIPToStr (3232235790) as ip
當然，對於mysql數據，就沒必要這麼麻煩了。完全可以使用內置的函數：inet_aton 和inet_ntoa
select inet_aton('192.168.1.12');
select inet_ntoa(3232235788);
