How to add row number or Serial no in laravel datatable

If you are using yajra laravel datatables

Just add ->addIndexColumn()

return DataTables::of($data)
            ->addIndexColumn()
            ->make(true);

In your javascript, you can set the first row as a serial number like this

columns: [
            { data: 'DT_RowIndex', name: 'DT_RowIndex', orderable: false, searchable: false },
            { data: 'name', name: 'name' },
            { data: 'action', name: 'action' }
        ]

use DT_Row_Index instead of DT_RowIndex for older yajra datatable version

When using Yajra Laravel datatables

return DataTables::of($result)
            ->addIndexColumn()
            ->make(true);

"columns": [
                {
                    "data": 'DT_RowIndex',
                    orderable: false, 
                    searchable: false
                },
]

Set the variable rownum at the beginning of your query. Then set the increment process in your query.

DB::statement(DB::raw('set @rownum=0'));

$data = BillInfo::get(['bill_info.*', 
                    DB::raw('@rownum  := @rownum  + 1 AS rownum')]);

return Datatables::of($data)
                ->removeColumn('id')
                ->make(true);

Here you can get rownum as serial no of the given records [1 . . . 8].

In Laravel Yajra Datatables v9.x as Service Implementation, I add this in getColumns function and works well in sorting, searching, and page changing.

'id' => ['title' => 'N.', 'orderable' => false, 'searchable' => false, 'render' => function() {
            return 'function(data,type,fullData,meta){return meta.settings._iDisplayStart+meta.row+1;}';
        }],