title: Where clause without operator
body: <p>While trying to answer <a href="https://stackoverflow.com/questions/30885007/difference-in-resultsin-mysql-and-if-condition-for-nulls-applied#comment49810836_30885007">this question</a>, I found a syntax which I would have considered wrong</p>
  
  <pre><code>select * from table where area and block
  </code></pre>
  
  <p>I tried an sqlFiddle, and found it was valid.</p>
  
  <p>But I've been unable to find how it works (all the doc I found was including operators)...</p>
  
  <p>Made some try on an sql fiddle <a href="http://sqlfiddle.com/#!9/7a7703/1" rel="nofollow noreferrer">here</a></p>
  
  <p>It seems to "eliminate" null and 0 results for an nullable int field, or 0 result for a non nullable int field.</p>
  
  <p>It also looks like it keeps varchar values... which contains int values (but not '0') !</p>
  
  <p>Even if I don't think it's a good idea (at all) to use such syntax, I would appreciate if someone had any explanation on how this is managed...</p>