Oracle - ¿Como establecer una condicion WHERE al resultado de un COUNT en OracleSQL?

select x.numrut as "RUT EMPLEADO", x.pnombre ||' '|| x.appaterno as "NOMBRE EMPLEADO", count( z.monto_total) as TOTAL_VENTAS

from empleado x full join ventas z

on z.id_empleado=x.id_empleado

where z.monto_total<2

group by x.appaterno, x.numrut, x.pnombre

order by TOTAL_VENTAS asc;

SELECT x.numrut AS "RUT EMPLEADO",

         x.pnombre || ' ' || x.appaterno AS "NOMBRE EMPLEADO",

         COUNT (z.monto_total) AS TOTAL_VENTAS

    FROM empleado x FULL JOIN ventas z ON z.id_empleado = x.id_empleado

GROUP BY x.appaterno, x.numrut, x.pnombre

  HAVING  COUNT (z.monto_total) < 2

ORDER BY TOTAL_VENTAS ASC;