This bug may manifest itself for select queries over a multi-table view
that includes an ORDER BY clause in its definition. If the select list of 
the query contains references to the same view column with different
aliases the names of the columns in the result output will be nevertheless
the same, coinciding with one of the alias.

The bug happened because the method Item_ref::get_tmp_table_item that
was inherited by the class Item_direct_view_ref ignored the fact that
the name of the view column reference must be inherited by the fields
of the temporary table that was created in order to get the result rows
sorted.


mysql-test/r/view.result:
  Added a test case for bug #29392.
mysql-test/t/view.test:
  Added a test case for bug #29392.
sql/item.h:
  Fixed bug #29392.
  This bug may manifest itself for select queries over a multi-table view
  that includes an ORDER BY clause in its definition. If the select list of 
  the query contains references to the same view column with different
  aliases the names of the columns in the result output will be nevertheless
  the same, coinciding with one of the alias.
  
  The bug happened because the method Item_ref::get_tmp_table_item that
  was inherited by the class Item_direct_view_ref ignored the fact that
  the name of the view column reference must be inherited by the fields
  of the temporary table that was created in order to get the result rows
  sorted.
  
  Fixed by providing a proper implementation of the get_tmp_table_item 
  method for the Item_direct_view_ref class.