title: SQL Server unpivot columns
body: <p>I have a table that I would like to unpivot in a SQL statement. It consists of a person and phone 1 through 5. Right now I'm doing a union for each phone but I fear it is causing performance issues.</p>
  
  <p>Columns:</p>
  
  <pre><code>PERSON_GUID, 
  PHONE_1, PHONE_1_VOICE_FLG, 
  PHONE_2, PHONE_2_VOICE_FLG, 
  PHONE_3, PHONE_3_VOICE_FLG, 
  PHONE_4, PHONE_4_VOICE_FLG, 
  PHONE_5, PHONE_5_VOICE_FLG
  </code></pre>
  
  <p>How would I best unpivot the row with performance in mind so that the results are:</p>
  
  <pre><code>PERSON_GUID, PHONE_NO, VOICE_FLG
  </code></pre>