title: Populate a WTForms SelectField with an SQL query
body: <p>I'm want to populate a WTForms SelectField with the rows returned by this query:</p>
  
  <pre><code>cur.execute("SELECT length FROM skipakke_alpin_ski WHERE stock &gt; 0")
  </code></pre>
  
  <p>The query returns rows with the ski length of different types of skis. <code>cur.fetchall()</code> returns the following tuple:</p>
  
  <pre><code>[(70,), (75,), (82,), (88,), (105,), (115,), (125,), (132,), (140,), (150,), (160,), (170,)]
  </code></pre>
  
  <p>How would I go about to do add these numbers to a <code>SelectField</code>, so that each ski length would be its own selectable choice? If I had done this manually, I would have done the following:</p>
  
  <pre><code>ski_size = SelectField('Ski size', choices=['70', '70', '75', '75'])
  </code></pre>
  
  <p>... And so on for all of the different lengths.</p>