Question

我有以下sql语句：

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

我想将这3列的结果合并到一个虚拟列 - messaging。例如，如果p.opt_in_to_receive_reminders为真并且u.phone_number不为空且p.receive_reminders为真，则此列将具有真值，在其他情况下，它将返回false。

我如何在PostgreSQL中执行此操作？

Answer 1

请写下：

p.opt_in_to_receive_reminders为true，如果u.phone_number不为空且p.receive_reminders为真

作为

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

将三列合并为一列

1 个答案: