title: What does a SELECT statement without FROM used for?
body: <p>I am analyzing a stored procedure.
  There I came across a <code>SELECT</code> statement as below.</p>
  
  <pre><code>select @msg = 'spid: ' + convert(varchar(12), @@spid) + ' pre mat pull - PRODUCT_WORK COUNT = ' + convert(char(6), @@rowcount)
  </code></pre>
  
  <p>What does this statement without <code>FROM</code> do? How does it work? When do we use it?</p>
  
  <p>Can't we use <code>SET</code> instead of <code>SELECT</code>?</p>
  
  <p>Please help.</p>