Joining Multiple DataTable to One DataTable

I have 3 datatable dt,dt1,dt2....I am performing a join operations..

var query = from p in dt.AsEnumerable()
                  join a in dt1.AsEnumerable()
                  on p.Field<int>("LId") equals a.Field<int>("LId")
                  join t in dt2.AsEnumerable()
                  on a.Field<int>("LId") equals t.Field<int>("LId")
                  select new
                  {
                      EmpId = p.Field<int>("EmpId"),

                      EmpName = p.Field<string>("EmpName"),
                      LocationName = a.Field<string>("LocationName")
                  };
when i run this query i am getting error as Column 'LId' does not belong to table Table3.