Custom fields is probably the wrong term. In my query I have
SELECT tblPatient.Patient_Name, tblEpisode.EpisodeID, tblPatient.Unit_Number, tblPatient.PatientID, tblPatient.DOB, tblPatient.Gender, tblPatient.Postcode, tblPatient.Ethnic_Origin, tblPatient.GP_DR, tblEpisode.Date_Referred...