將三列合並為一個

Question

我有以下sql語句：

SELECT p.id, p.first_name, p.last_name, a.admitted_at,
       a.discharged_at, c.name as client_name, p.receive_reminders,
       p.opt_in_to_receive_reminders, u.phone_number, p.status,
       c.id as client_id, p.mrn
  FROM patients p
  LEFT JOIN admissions a ON p.last_admission_id = a.id
  INNER JOIN facilities f ON f.id = p.facility_id
  INNER JOIN clients c ON c.id = f.client_id
  LEFT OUTER JOIN users u ON p.user_id = u.id;

我有三列：

p.opt_in_to_receive_reminders - boolean
u.phone_number - string
p.receive_reminders - boolean

我想將這3列的結果合並到一個虛擬列messaging 。 例如，如果p.opt_in_to_receive_reminders為true，並且u.phone_number不為空，並且p.receive_reminders為true，則此列將為true，在其他情況下它將返回false。

如何在PostgreSQL中做到這一點？

Answer 1

只需寫下：

p.opt_in_to_receive_reminders為true，並且如果u.phone_number不為空且p.receive_reminders為true

如

select p.opt_in_to_receive_reminders and u.phone_number is not null and p.receive_reminders
-- or
select p.opt_in_to_receive_reminders and u.phone_number <> '' and p.receive_reminders
-- or
select p.opt_in_to_receive_reminders and coalesce(u.phone_number, '') is null and p.receive_reminders