Retrieve ListItem data Using CAML in SharePoint 2013

The following code snippet can be used to programmatically retrieve list item data Using CAML

 SPWeb web = SPContext.Current.Web;

            SPList list = web.Lists["Documents"];

            SPQuery query = new SPQuery();

            query.ViewFields = "<FieldRef Name='ID'/>" +"<FieldRef Name='Title'/>" + "<FieldRef Name='LastName'/>" +"<FieldRef Name='Age'/>";

            SPListItemCollection item = list.GetItems(query);

            GridView1.DataSource = item.GetDataTable();

            GridView1.DataBind();