Este querie nos brinda los abonados que solo poseen el servicio CATV, el cual se compone de los servicios 99 y 01.

Select a.prefijo, a.abofecalta, e.EMAIL ,t.cod_zona,t.telefono, c.desccat,a.datcodest, a.Abonumero,a.abonombre
from abonados as A, emails as E, telefono as t, categor as c
where e.abonumero = a.abonumero
and c.codcat = a.datcategor
and t.abonumero = a.abonumero
And a.abonumero in 
(
select DISTINCT  ABONUMERO from aboservi where datcodserv in ('99','01')  and absfedesc='1900-01-01' and abonumero in 
(
select abonumero from aboservi where datcodserv <> '99' AND datcodserv <> '01' and absfedesc='1900-01-01'
)
)
and a.datcodest = '1'