ZF-5953: Support joining with multiple columns with joinUsing
Currently, if you need to join on multiple columns, you cannot use joinUsing();
The join condition should accept an array of columns to join on.
SELECT * FROM table1 JOIN table2 USING (column1, column2)
$select = $db->select() ->from('table1') ->joinUsing('table2', array('column1','column2'));
Originally suggested here: ZF-1845, but was only half implemented.