linq using where contains groupby select and orderby

Requirement:

1) Get the distinct nationalcodes from the table TestConcodes

2) Get the names of the codes obtained in the step above by querying the table refCodes, but refCodes table might have more than one record for each code, so I just need to pick one row for each code and then to order by based on code text.

I have written the code as below and it seems to be working, but I am wondering is there any flaw in this or can there be any better linq code to get my requirement.

var records = context.TestConcodes.Select(c => c.NationalCode).Distinct();

                    if (records.Count() > 0)
                    {
                        var results = context.refCodes
                            .Where(c => records.Contains(c.CodeValue))
                            .GroupBy(a => a.CodeValue)
                            .Select(g =>g.FirstOrDefault())
                            .OrderBy(c => c.CodeText).ToList();
					}

					ddlOutput.DataSource = results;
                            ddlOutput.DataTextField = "CodeText";
                            ddlOutput.DataValueField = "CodeValue";
                  }