title: php sql merge 2 queries
body: <p>I have 2 queries one straight after the other:</p>
  
  <pre><code>$sql_result8 = mysql_query("SELECT * FROM properties WHERE c4='$id'", $db); $charges = mysql_num_rows($sql_result8); 
  $sql_result8 = mysql_query("SELECT * FROM vehicles WHERE c4='$id'", $db); $charges = $charges + mysql_num_rows($sql_result8);
  </code></pre>
  
  <p>What kind of query would I need to merge these? Some kind of JOIN? UNION? </p>