Question: I currently have this code which saves all the information to the database but I want to be able to allow users to search using their postcode so only results within the radius they select is shown eg. 1mile, 2mile etc I am not sure how to go about doing this.

```
 <form action="addhobby.php" method="POST">
 Type:<input type="radio" name="type" value="meetup" checked>Meetup
<input type="radio" name="type" value="chat" checked>Chat
<br />

Hobby:<input type="text" name="hobby" value=""><br />

Location:<input type="text" name="location" value=""><br />
Postcode:<input type="text" name="postcode"><br />

Starts:  <input type="date" name="startdate"> <input type="time" name="starttime"><br />
Ends: <input type="date" name="enddate"> <input type="time" name="endtime"> <br />

Description: <input type="text" name="description"><br />

<input type="submit" name="submit" value="Create">

```

```
<?php
$con = mysql_connect("localhost","root","");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("test", $con);

   $sql="INSERT INTO activities (hobby, location, postcode, sdate, stime, edate,    etime, description, type) VALUES
('$_POST[hobby]','$_POST[location]', '$_POST[postcode]', '$_POST[startdate]', '$_POST[starttime]', '$_POST[enddate]', '$_POST[endtime]', '$_POST[description]', '$_POST[type]' )";

if (!mysql_query($sql,$con))
  {
  die('Error: ' . mysql_error());
  }
 header("location:profile.php");

mysql_close($con)
?> 

```

Answer: 
Why using postcode if you can get latitude and longitude with HTML5 Geolocation API?

You can use the following SQL statement:

```
SELECT id, ( 3959 * acos( cos( radians(37) ) * cos( radians( lat ) ) * cos( radians( lng ) - radians(-122) ) + sin( radians(37) ) * sin( radians( lat ) ) ) ) AS distance FROM markers HAVING distance < 5 ORDER BY distance;

```

You must replace `lat` with a latitude and `lng` with a longitude. To search by kilometers instead of miles, replace 3959 with 6371.

**Source**: <https://developers.google.com/maps/articles/phpsqlsearch_v3>
To do this you will need a zip code database which provides latitude and longtitude coordinates for each zip code. If you have this data, then you can query all the ZIP codes which are located between a specified distance.

You can use an open source zip code database like [this](http://zips.sourceforge.net/) (for US only).