title: Length vs Precision
body: <p>When I describe a table with <code>nvarchar</code> data type, what's the difference between <code>Precision</code> and <code>Length</code>? I see that <code>Length</code> is always the double. For example the values is <code>nvarchar(64)</code>, the precision is 64 and the length is 128.</p>
  
  <pre><code>CREATE TABLE T(X nvarchar(64))
  EXEC sp_columns 'T'
  </code></pre>