EXPLAIN ANALYZE
  WITH 
    --
    -- Datos unicos y calculados a capturar (DU y DCC)
    --
    du AS
    (
      SELECT idprodxintegrar, a.idb2, a.idc1, tipo, valor, estado, idsll, idsfte, b.nodec,
              b.rama _match --sera nulo si no hay match
        FROM _gc_tb a
        LEFT  join
             _gc_cat b
             on ( a.arama <@ b.arama and a.arama @>  b.arama ) 
    )select * from du;
