indivisual column filter in datatables

sarojdatatable

/* Define two custom functions (asc and desc) for string sorting */

$(document).ready(function() {
oTable = $('#listing').dataTable( {
"bProcessing": true,
"bServerSide": true,
"sAjaxSource": "master_distributor/productsList.php",
"aoColumns": [
{ "mData": "product_name" },
{"mData": "product_id"},
{ "mData": "parent_id","sClass": "txtCenter" },
{ "mData": "action",'bSortable': false,"sClass": "txtCenter" }
],

}).columnFilter({
aoColumns: [ { type: "text"},
{ type: "text" },
{ type: "text" },
null

]

});

} );



In above i want to add action as a column in my datatable.
but it is not working.
Here action is the json resoponse from my ajax page