title: Select from unknown table name
body: <p>How i can got online from different tables ?</p>
  
  <pre><code>SELECT count(online) FROM (SELECT UserTableName FROM `name`) WHERE online = 1
  
  
  --------------
  UserTableName
  --------------
  users_1
  users_2
  users_3
  
  --------------
  users_x
  --------------
  1
  0
  0
  1
  </code></pre>
  
  <p>I need get online and table names from tables different tables example:</p>
  
  <pre><code>-----------------
   online | table
  -----------------
         5| users_1
         3| users_2
         9| users_3
  </code></pre>