Column not found: 1054 Unknown column '0' in field list

i have 3 forms in one page using ajax for them. Edit form is getting error as below. I dont know why i am getting this error. I am beginner. error while submitting form:

"SQLSTATE[42S22]: Column not found: 1054 Unknown column '0' in 'field list' (SQL: update user_profiles set 0 = , updated_at = 2018-08-18 10:25:43 where id = 1)"

This is my edit button code:

<a class="btn btn-primary" href="javascript:void(0);" onclick="editExchangeMarket();">
    <span class="glyphicon glyphicon-edit"></span> Edit
</a>

This is my modal and ajax code:

<script>
        function updateExchangeMarket() {
            var edit_fid = $('#edit_fid').val();
            var edit_charge_per_lot = $('#edit_charge_per_lot').val();
            $('#exchangeMarketModal').modal('show');
            //   alert(values);
            $.ajax({
                headers: {'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content') },
                url: "",
                data:{'id' : edit_fid, 'edit_charge_per_lot':edit_charge_per_lot},
                method:'POST',
                success: function( resp ) {
                    },
                error: function( req, status, err ) {
                console.log( 'something went wrong', status, err );
                    }
            });

        }
</script>

<div id="exchangeMarketModal" class="modal fade" role="dialog">
    <div class="modal-dialog">
        <!-- Modal content-->
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal">&times;</button>
                <h4 class="modal-title">Modal Header</h4>
            </div>
            <div class="modal-body">
                <form id="exchangeMarketForm" name="exchangeMarketForm" >
                    <input type="hidden" class="form-control" id="edit_fid" value="1">

                    <div class="col-md-6 mb-3 form-group">
                        chargeperlot: <input type="text" name="edit_charge_per_lot" id="edit_charge_per_lot" class="form-control"><br>
                    </div>
               
                </form>
            </div>
            <div class="modal-footer">

                <a type="submit" href="javascript:void(1);" onclick="updateExchangeMarket();" value="Submit" class="btn btn-primary">Save changes</a>
                <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
            </div>
        </div>

    </div>
</div>

Now i am adding here my controller code:

        public function updateExchangeMarket(Request $request)
    {
        $id = $request->id;    
        $charge_per_lot = $request->edit_charge_per_lot;

        $data = array('country_id'=>$country_id,
            'id'=>$id,
            'charge_per_lot'=>$charge_per_lot,

        );
        $res = UserProfile::where('id',$id)->update([$data]);
        echo json_encode($res);
    }

via Chebli Mohamed