Questo dovrebbe dare il risultato corretto:
select
id,
min(startDate) as startFreeDate,
count(*) - (endDate is null) numFreeDays
from (
select
pb1.id,
pb1.bookingDate startDate,
min(pb2.bookingDate) endDate
from
pricesBookings pb1 left join pricesBookings pb2
on pb1.id=pb2.id
and pb2.price>0
and pb2.bookingDate>pb1.bookingDate
where
pb1.price=0
group by
pb1.id,
pb1.bookingDate
) s
group by id, endDate
order by id, startDate
guardalo qui .
Se devi cercare tutti gli slot gratuiti di, ad esempio, 14 giorni, puoi aggiungere HAVING:
group by id, endDate
having count(*) - (endDate is null) >= 14
order by id, startDate
