Federated table of two LEFT JOIN tables not working
To define a FEDERATED table the field definition on local table much match field types on remote table. You are creating a brand new table by joining existing tables. I don't think this is legal.


  A local server with a database table, where the table definition
  matches that of the corresponding table on the remote server. The
  table definition is stored within the .frm file. However, there is no
  data file on the local server. Instead, the table definition includes
  a connection string that points to the remote table.


http://dev.mysql.com/doc/refman/5.5/en/federated-description.html