I followed this blog http://blogs.lessthandot.com/index.php/DataMgmt/DataDesign/sql-server-2008-proximity-search-with-th and did everything which was guided and I am glad things went fine, my table definition is mentioned below and the query I am executing is also mentioned below.
I am using CodePointData data which is downloadable from https://www.ordnancesurvey.co.uk/opendatadownload/products.html
USE [TestDb] GO /****** Object: Table [dbo].[PostCode] Script Date: 08/23/2012 05:32:05 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[PostCode]( [PostCode] [nvarchar](10) NOT NULL, [Coordinates] [geography] NOT NULL, [Coordinates1] [geography] NULL, CONSTRAINT [PK_PostCode] PRIMARY KEY CLUSTERED ( [PostCode] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON)
ON [PRIMARY] ) ON [PRIMARY]
SELECT distinct(left(h.postcode,4)) from postcode g join postcode h on g.postcode <> h.postcode and g.postcode ='IG1 4LF' and h.postcode <> 'IG1 4LF' Where g.coordinates.STDistance(h.coordinates)<=(1*1609.344) order by left(h.postcode,4)
When I am running the above query it is giving lots of postcodes which are not part of that Radius. I am verifying my results with another site http://www.freemaptools.com/find-uk-postcodes-inside-radius.htm and this site is saying that 1 Mile of Radius contains postcode IG1,IG2,IG3, but when I am running the above query my results are coming as E12,IG1,IG2,IG3,IG4,IG5,IG6. Which I am unable to find out why it is giving me this much or post codes in just mile of Radius.