mysql - MySQL 按最后一个条目分组

Question

我的表 payment_status 有这些字段：

• ID
• 付款ID
• 地位
• 创建
• 由...制作

许多条目可能具有相同的 payment_id... 所以，我想获得一个 payment_id 的最后状态...

我有这个可以工作的请求，但加载时间太长......我想要一个优化版本来按 payment_id 分组并获取最后一个状态。

SELECT pstatus.*
FROM `payment_status` AS pstatus
WHERE pstatus.id = (
   SELECT id
   FROM `payment_status`
   WHERE pstatus.status = '200'
   ORDER BY created DESC
   LIMIT 1
)
GROUP BY pstatus.payment_id
ORDER BY pstatus.payment_id DESC

Answer 1

试试这个查询 -

SELECT t1.* FROM payment_status t1
  JOIN (SELECT payment_id, MAX(created) max_created
        FROM payment_status
        GROUP BY payment_id
        ) t2
    ON t1.payment_id = t2.payment_id AND t1.created = t2.max_created;

...然后添加您需要的 WHERE 条件。

Answer 2

尝试使用JOIN：

SELECT p1.*
FROM payment_status p1
INNER JOIN
(
    SELECT id, MAX(created) MaxCreated
    FROM payment_status 
    WHERE status = '200'
    GROUP BY id
) p2 ON p1.id = p2.id AND p1.created = p2.MaxCreated
ORDER BY p1.payment_id DESC

Answer 3

这应该工作

SELECT *
FROM  payment_status
WHERE status = '200'    
ORDER BY created DESC
LIMIT 1

Answer 4

你不应该能够做到这一点吗？：

（假设 created 是时间戳，所以 "last" = "most recent"）

SELECT pstatus.*
FROM `payment_status` AS pstatus
GROUP BY pstatus.payment_id, pstatus.status
ORDER BY pstatus.payment_id DESC, pstatus.created DESC

每行返回都应该有具有最新状态的 payment_id。

Answer 5

我想你正在使用 MySQL 数据库。

在这里，我有一个快速且易读的解决方案：

select 
    substring_index(
        group_concat(status order by created desc)
        , ',', 1
    ) as status_latest 
from payment_status 
group by payment_id

我很确定它比其他 SQL 语句快，你可以试试。