title: One select, two tables and no join
body: <p>I stumble upon below sql-code (translated for sample purpose) :</p>
  
  <pre><code>SELECT m.username, c.companyname 
  FROM member m , company c 
  WHERE m.id = 5 AND c.id = 10;
  </code></pre>
  
  <p>Table members has <code>id</code> as PK. Company has <code>id</code> as PK. There is no relation between these two tables.
  At first I didn't think this would work, but it did.</p>
  
  <p>Result is one row with value for <code>username</code> and <code>companyname</code>.</p>
  
  <p>Before I saw this solution I would have gone for 2 sql - one for <code>member</code> and one for <code>company</code>.</p>
  
  <p>What is the possible danger with this SQL?</p>