获取给定状态的状态历史表中的最后更新时间

Question

我有这张桌子 order_status_history，每次更新订单时我都会插入一行，假设一个表只有列 id：

id	order_id	order_status_id	updated_at
1	121	ready	2021-12-30 10:00:00
2	121	shipped	2021-12-30 10:01:00
3	121	ready	2021-12-30 10:02:00
4	121	shipped	2021-12-30 10:03:00
5	121	delivered	2021-12-30 10:04:00

我需要获取所有订单 (DISTINCT) 的最新 updated_at 值，这些订单 (DISTINCT) 作为最后状态已发货，或者如果已交付出于任何原因，没有已发货状态。

我写了这个查询，但我得到了 delivered 状态的最后一个 updated_at 值。在示例情况下，我需要 updated_at 作为 10:03，但我得到的是 10:04。

SELECT o.id, 
       osh.max_updated_at AS updatedAt
FROM orders o
JOIN  ( SELECT order_id, 
               Max(updatedat) AS max_updated_at
        FROM   order_status_history
        WHERE  order_status_id IN('shipped','delivered')
        GROUP  BY order_id
      ) AS osh ON osh.order_id = o.id
AND ( SELECT order_status_id
      FROM order_status_history
      WHERE  order_id = o.id
      ORDER  BY updatedat DESC
      LIMIT 1 
     ) IN('shipped','delivered')

Answer 1

用子查询试试这个

SELECT id, (
  SELECT h.updated_at
  FROM order_status_history h
  WHERE h.order_id = o.id
  AND h.order_status_id IN ('shipped','delivered')
  AND NOT EXISTS (
    SELECT 1
    FROM order_status_history k
    WHERE k.order_id = h.order_id
    AND k.updated_at > h.updated_at
    AND k.order_status_id NOT IN ('shipped','delivered')
  )
  ORDER BY CASE WHEN order_status_id = 'shipped' THEN 1 ELSE 2 END ASC, updated_at DESC
  LIMIT 1
) AS updatedAt
FROM orders o

如果您选择单个列，则子查询有效

这是 MySQL8+ 的另一个选项

WITH ordered AS (
  SELECT *, ROW_NUMBER() OVER(PARTITION BY order_id ORDER BY CASE WHEN order_status_id = 'shipped' THEN 1 ELSE 2 END ASC, updated_at DESC) rn
  FROM order_status_history
  WHERE order_status_id IN ('shipped','delivered')
)
SELECT o.id, h.*
FROM orders o
LEFT JOIN ordered h ON o.id = h.order_id 
  AND h.rn = 1 AND NOT EXISTS (
    SELECT 1
    FROM order_status_history k
    WHERE k.order_id = h.order_id
    AND k.updated_at > h.updated_at
    AND k.order_status_id NOT IN ('shipped','delivered')
  )