Você terá que separar o intervalo, dos dos documentos
Para fazer isso, você pode usar
lower , e upper
SELECT tsrange( lower(freetime), lower(appointment) ) AS before_appointment,
tsrange( upper(appointment), upper(freetime) ) AS after_appointment
FROM ( VALUES
(
'[2017-04-19 09:00, 2017-04-19 12:30)'::tsrange,
'[2017-04-19 10:30, 2017-04-19 11:30)'::tsrange
)
) AS t(freetime,appointment)
WHERE freetime @> appointment;
before_appointment | after_appointment
-----------------------------------------------+-----------------------------------------------
["2017-04-19 09:00:00","2017-04-19 10:30:00") | ["2017-04-19 11:30:00","2017-04-19 12:30:00")
(1 row)
