Is there a better way to do update PostgreSQL - postgresql

Question

I'm trying to update the ended_at and active columns in the test_subscription table when the max period_end has not passed.
I'm using the below query but I doubt it's the most idiomatic way. Any suggestions on improvements are very much welcome.
Creating the tables:
CREATE TABLE test_subscription (
id INTEGER PRIMARY key,
started_at timestamp,
ended_at TIMESTAMP,
active boolean
);
CREATE TABLE test_invoice (
id INTEGER PRIMARY key,
subscription_id INTEGER,
period_start timestamp,
period_end timestamp
);
INSERT INTO test_subscription (id, started_at, ended_at, active)
values(1, '2017-01-01 00:00:00', NULL, TRUE);
INSERT INTO test_subscription (id, started_at, ended_at, active)
values(2, '2017-01-01 00:00:00', NULL, TRUE);
INSERT INTO test_invoice (id, subscription_id, period_start, period_end)
values(1, 1, '2017-01-01 00:00:00', '2017-12-01 00:00:00');
INSERT INTO test_invoice (id, subscription_id, period_start, period_end)
values(2, 1, '2017-12-02 00:00:00', '2019-12-01 00:00:00');
INSERT INTO test_invoice (id, subscription_id, period_start, period_end)
values(3, 2, '2017-01-01 00:00:00', '2017-12-01 00:00:00');
I'm updating using the below.
UPDATE test_subscription
SET ended_at = (CASE WHEN (SELECT
MAX(period_end)
FROM test_invoice
WHERE test_subscription.id = test_invoice.subscription_id
) < now()
THEN (SELECT MAX(period_end)
FROM test_invoice
WHERE test_subscription.id = test_invoice.subscription_id
)
ELSE NULL
end),
active = (CASE WHEN (SELECT MAX(period_end)
FROM test_invoice
WHERE test_subscription.id = test_invoice.subscription_id
) < now()
THEN TRUE
ELSE FALSE
end);

Answer 1

Updates like that are usually faster if you first collect all the aggregates, then run the update using that intermediate result. Co-related sub-queries tend to be much slower.
update test_subscription s
set ended_at = case when t.latest_end < current_timestamp then t.latest_end end,
active = t.latest_end < current_timestamp
from (
select s.id,
max(i.period_end) as latest_end
from test_subscription s
join test_invoice i on s.id = i.subscription_id
group by s.id
) t
where t.id = s.id;
Online example: http://rextester.com/NMMF41667

Answer 2

You can put the MAX within CASE
UPDATE test_subscription s
SET ( ended_at, active ) = (SELECT MAX(CASE
WHEN period_end < NOW() THEN
period_end
END),
MAX(CASE
WHEN period_end < NOW() THEN 'TRUE'
ELSE 'FALSE'
END) :: BOOLEAN
FROM test_invoice i
WHERE s.id = i.subscription_id);
Demo