title: Is it faster to check if length = 0 than to compare it to an empty string?
body: <p>I've heard that in some programming languages it is faster to check if the length of a string is <code>0</code>, than to check if the content is <code>""</code>. Is this also true for T-SQL?</p>
  
  <p>Sample:</p>
  
  <pre><code>SELECT user_id FROM users WHERE LEN(user_email) = 0
  </code></pre>
  
  <p>vs.</p>
  
  <pre><code>SELECT user_id FROM users WHERE user_email = ''
  </code></pre>