title: SQL... How to update rows with data from other rows in the same table?
body: <p>I'm using MySQL server and I have a table where some rows are missing data.  I would like to update the rows using information from other rows.  My table looks something like:<br /></p>
  
  <pre>
  id,signin,deviceId,deviceModel
  1,2010-10-12,9ABC9,
  2,2010-10-12,3E44F,
  3,2010-10-13,D3453,
  4,2010-10-14,D3453,
  5,2010-10-14,D3453,HW1
  6,2010-10-12,3E44F,HW2
  7,2010-10-12,9ABC9,HW1
  </pre>
  
  <p>For the first few entries, the deviceModel field is empty.  I would like to update this value using the deviceModel found for the deviceId in other rows of this same table. In the example above, row 1 should have deviceModel = HW1, row 2 should have deviceModel = HW2, etc.</p>
  
  <p>Thanks!</p>