SELECT FINAL_SITE.Site_Information, FINAL_SITE.Date, FINAL_SITE.[CH-X], FINAL_SITE.[CH-Y], DATA_FROM_GIS.Lon, DATA_FROM_GIS.Lat, FINAL_SITE.Precision, FINAL_SITE.[Field Elevation], DATA_FROM_GIS.DEM_Elevation, FINAL_SITE.Comment
FROM FINAL_SITE LEFT JOIN DATA_FROM_GIS ON...