title: mySQL returns all rows when field=0
body: <p>I was making some tests, and it was a surprise when i was querying a table, and the query <code>SELECT * FROM table WHERE email=0</code> returned all rows from the table.</p>
  
  <p>This table has no '0' values and it's populated with regular e-mails.</p>
  
  <p>Why this happens? This can lead to serious security problems.</p>
  
  <p>Is there a way to avoid this without modifying the query?</p>
  
  <p>Am i missing something here?</p>
  
  <p>Thanks.</p>