I am trying to use a join query in Magento Abandoned Grid this way:

     $collection->getSelect()->joinLeft(
                            'abandoned_comment_history', 'main_table.customer_id=abandoned_comment_history.customer_id', array('admin_comment', 'comment_datetime', 'status'))
                    ->group('main_table.customer_id');

In my custom table **abandoned_comment_history** there are multiple matches with main **table.customer_id** & i am getting the **first one** but i need **last one**.

Is there any way to get the last match from my custom table. 
I searched a lot but couldn't find the solution. Hope will get here.

Description: In my table **abandoned_comment_history** have some data as

    id customer_id admin_comment
    1     2082      Test 1
    2     2082      Test 2
    3     2091      Hello

In main_table customer_id column is unique.

      customer_id 
         2082      
         2084      
         2091      

Now if i try to **join & get admin_comment** value i get "Test 1" but i need "Test 2"