MySQL查詢得到集團的SUM和最後一個記錄值BY

Question

我有兩個表1是帳戶，另一種是account_spend_history灰分帳戶是父/主表和噓一張小桌子。並與賬戶OneToMany有關係（賬戶表id是ash中的一個外鍵，如account_id）。請看圖片

現在我需要獲取account.id，總花費（這是amount_spend與相同的account_id的總和）和最後花費（是在灰表中插入的最後一條記錄，並且account_id即amount_spend值與MAX（ash.id））對應的，即

id | spend_total | last_spend 
--------------------------------- 
1 | 30   | 18 
2 | 280   | 120 
3 | 20   | 20

SELECT a.id, SUM(ash.amount_spend) AS spend_total 
FROM accounts as a 
INNER JOIN account_spend_history AS ash ON ash.account_id = a.id 
GROUP BY a.id

即時得到ash.amount支出的account.id和總和，但我還需要最後的支出。如何獲得？

感謝。

Answer 1

下面是一個使用correlated subquery一個選項：

SELECT a.id, SUM(ash.amount_spend) AS spend_total, 
     (SELECT amount_spend 
     FROM account_spend_history as ash2 
     WHERE ash2.account_id = a.id 
     ORDER BY ash2.id DESC LIMIT 1) as last_spend 
FROM accounts as a 
    INNER JOIN account_spend_history AS ash ON ash.account_id = a.id 
GROUP BY a.id 

Answer 2

可以在子句中使用和子查詢

SELECT a.id, SUM(ash.amount_spend) AS spend_total, x.last_spend 
FROM accounts as a 
INNER JOIN account_spend_history AS ash ON ash.account_id = a.id 
INNER JOIN ( 
    select account_id, last_spend, start_date 
    from account_spend_history 
    where (start_date, acoount_id) in ( 
     select max(start_date), account_id 
     from account_spend_history 
     group by account_id 
    ) 
) x on x.id = a.id 
GROUP BY a.id 

Answer 3

你可以得到MAX(ash.id)以及在您的查詢，然後用它來連接回到account_spend_history表格：

SELECT id, spend_total, amount_send as last_spend 
FROM (
    SELECT a.id, SUM(ash.amount_spend) AS spend_total, MAX(ash.id) AS ash_id 
    FROM accounts as a 
    INNER JOIN account_spend_history AS ash ON ash.account_id = a.id 
    GROUP BY a.id) AS t1 
INNER JOIN account_spend_history AS ash ON ash.id = t1.ash_id