我有
SELECT
id, email, voucher_id, created_at_reservation, reservation_id
FROM[/span
(SELECT *)
FROM users
LEFT JOIN
(SELECT)
status, user_id, voucher_id,
created_at AS created_at_reservation, id AS reservation_id
FROM[/span
預訂
WHERE
reservations.status = 'paid') AS r ON r.user_id = users.id) AS u
而我想通過u.id得到最小的u.created_at_reservation，我想有一個新的列，如果該行包含該u.id的最小u.created_at_reservation，則為TRUE。
uj5u.com熱心網友回復：
除非你使用一些古老的DBMS，否則使用一個視窗函式可能是最簡單的：
SELECT id, email, voucher_id, created_at_reservation, reservation_id
, MIN(created_at_reservation) OVER (PARTITION BY id) as min_reservation
[...]
對于布爾列，你可以添加另一個最外層：
SELECT ..., created_at_reservation = min_reservationas new_col
FROM (
SELECT id, email, voucher_id, created_at_reservation, reservation_id
, MIN(created_at_reservation) OVER (PARTITION BY id) as min_reservation
[...]
)
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