title: mysql speed mysql_num_rows vs query limit 1
body: <p>i had to check if a value (string) is in my database.</p>
  
  <p>at the moment i do a  </p>
  
  <p><code>select a.email,b.vuid from user a, verteiler_user b where a.email=\''.$email.'\' and a.kid=' . $kid.' and b.vid=' . $vid . ' and a.uid = b.uid</code></p>
  
  <p>as query with a <code>mysql_num_rows</code>, then check <code>if &gt;=1</code></p>
  
  <p>But is it faster to do a query with limit 1; ? and check if a row is coming back ?</p>