title: Finding Cities within 'X' Kilometers (or Miles)
body: <p>This may or may not be clear, leave me a comment if I am off base, or you need more information.  Perhaps there is a solution out there already for what I want in PHP.</p>
  
  <p>I am looking for a function that will add or subtract a distance from a longitude OR latitude value.  </p>
  
  <p>Reason: I have a database with all Latitudes and Longitudes in it and want to form a query to extract all cities within X kilometers (or miles).  My query would look something like this...</p>
  
  <pre><code>Select * From Cities Where (Longitude &gt; X1 and Longitude &lt; X2) And (Latitude &gt; Y1 and Latitude &lt; Y2)
  
   Where X1 = Longitude - (distance)
   Where X2 = Longitude + (distance)
  
   Where Y1 = Latitude - (distance)
   Where Y2 = Latitude + (distance)
  </code></pre>
  
  <p>I am working in PHP, with a MySql Database. </p>
  
  <p>Open to any suggestions also! :)</p>