How to deal with duplicate table name with db_select left join
You can fetch data with drupal db_select as below code:-

$query= db_select('table1', 'column1');
$query-&gt;join('table2', 'column2', 'column1.column=column2.column'); 

$query=$query-&gt;fields('column1',array('column'))
       -&gt;fields('column2',array('column'))       
       -&gt;execute()-&gt;fetchAll();


For more information on db_select join queries click on this link