postgresql不支持,update.....limit 這樣的語法,所以可以這樣。
WITH cte AS (
SELECT server_ip -- pk column or any (set of) unique column(s)
FROM server_info
WHERE status = 'standby'
LIMIT 1 -- arbitrary pick (cheapest)
)
UPDATE server_info s
SET status = 'active'
FROM cte
WHERE s.server_ip = cte.server_ip
RETURNING server_ip;