Try changing this
  full outer join fi on bii.bistamp = fi.bistamp
  full outer join ft on fi.ftstamp = ft.ftstamp
  full outer join pn on fi.fistamp = pn.fistamp


to this
  left join fi on bii.bistamp = fi.bistamp
  left join ft on fi.ftstamp = ft.ftstamp
  left join pn on fi.fistamp = pn.fistamp