Intenta cambiar los gustos de...
count(select * from bookings where b.id_customer = c.id)
...a...
(select count(*) from bookings where b.id_customer = c.id)
Intenta cambiar los gustos de...
count(select * from bookings where b.id_customer = c.id)
...a...
(select count(*) from bookings where b.id_customer = c.id)