SELECT mf_generale.code_site, sites.libl_site, count(mf_generale.code_site) AS nb_parcel, sum(mf_generale.surface) AS tot_surf
   FROM mf_generale, sites
  WHERE mf_generale.code_site::bpchar = sites.code_site::bpchar
  AND sites.site_ln=true
  GROUP BY mf_generale.code_site, sites.libl_site
  ORDER BY mf_generale.code_site;