title: What type is INTERVAL in the function DATEPART?
body: <p>The code <code>select DATEPART(month,getutcdate())</code> returns an integer representing the numeric month value of the current date.
  The value <code>MONTH</code> is one of a number of predefined options for the interval parameter.
  What is the underlying data type of that interval value?</p>
  
  <pre><code>declare @date datetime = getutcdate()
  , @interval notNVarChar(16) = 'month' --what type should this be?  
                                        --Would it need quotes for assignment?
  
  select DATEPART(@interval, @date)
  </code></pre>