title: Athena Unload TEXTFILE with null
body: <p>I am currently utilizing the <code>UNLOAD</code> feature in AWS Athena, where I query something like:</p>
  <pre><code>UNLOAD (SELECT * FROM sometable) TO 's3://&lt;location&gt;' WITH (format = 'TEXTFILE', field_delimeter = ',')
  </code></pre>
  <p>This generates a bunch of <code>.gz</code> files.  My issue is that all the <code>null/empty</code> values have been converted to <code>\N</code>.  Is there a way to replace this with just an empty string?</p>
  <p>I did notice that if I just do <code>SELECT * FROM sometable</code>, basically not using unload, it seems to be what I want (without <code>\N</code>).  I would like to get similar results with the unload, if its possible.  There seems to be a <code>SERDEPROPERTIES</code> with <code>serialization.null.format</code> (for creating a table), but not sure how to use it with unload.</p>