MySQL - 加入最後一行相關表

Question

我有一個問題，我已經搜索並找不到可以提供任何幫助的答案。

有3個表格：orders,customers和teams。每個訂單都有一個客戶和一個團隊。我的問題是，對於每個客戶，我試圖得到他們的總訂單，然後被分配到他們最後一個訂單的團隊。

我的查詢到目前爲止（正常工作）：

SELECT c.id, MAX(o.timestamp) AS "Last Order", COUNT(o.id) AS "Total Orders", SUM(o.price) AS "Total Spend" 
FROM orders o 
LEFT JOIN customers c ON o.customer = c.id 
WHERE o.timestamp > '2012-01-01 00:00:00' 
GROUP BY c.id 
ORDER BY c.id 

我無法弄清楚如何加入team.name他們放置在最後一個順序，而不會影響我有查詢的其餘部分。

示例表和期望的結果：

客戶：

╔════╦═════════════╗ 
║ ID ║ NAME  ║ 
╠════╬═════════════╣ 
║ 1 ║ John Smith ║ 
║ 2 ║ Jim Jimmers ║ 
╚════╩═════════════╝ 

團隊：

╔════╦═════════════╗ 
║ ID ║ NAME  ║ 
╠════╬═════════════╣ 
║ 1 ║ Red   ║ 
║ 2 ║ Blue  ║ 
╚════╩═════════════╝ 

訂單：

╔═══════╦═════════════════════╦══════════╦══════╦═══════╗ 
║ ID ║  TIMESTAMP  ║ CUSTOMER ║ TEAM ║ VALUE ║ 
╠═══════╬═════════════════════╬══════════╬══════╬═══════╣ 
║ 34656 ║ 2012-03-04 14:23:44 ║  1 ║ 2 ║ 20 ║ 
║ 37345 ║ 2012-04-12 11:32:07 ║  2 ║ 2 ║ 25 ║ 
║ 38220 ║ 2012-07-18 09:53:54 ║  1 ║ 2 ║ 15 ║ 
║ 39496 ║ 2012-07-03 10:11:32 ║  1 ║ 1 ║ 38 ║ 
║ 41752 ║ 2012-09-17 19:34:05 ║  1 ║ 2 ║  9 ║ 
║ 43734 ║ 2012-11-23 07:52:12 ║  2 ║ 1 ║ 20 ║ 
╚═══════╩═════════════════════╩══════════╩══════╩═══════╝ 

如何選擇的結果，如：

╔════╦═════════════╦═════════════════════╦═══════════╦══════════════╦═════════════╗ 
║ ID ║ NAME  ║  LAST_ORDER  ║ TEAM_NAME ║ TOTAL_ORDERS ║ TOTAL_SPEND ║ 
╠════╬═════════════╬═════════════════════╬═══════════╬══════════════╬═════════════╣ 
║ 1 ║ John Smith ║ 2012-09-17 19:34:05 ║ Blue  ║   4 ║   82 ║ 
║ 2 ║ Jim Jimmers ║ 2012-11-23 07:52:12 ║ Red  ║   2 ║   45 ║ 
╚════╩═════════════╩═════════════════════╩═══════════╩══════════════╩═════════════╝ 

Answer 1

我喜歡做這個用group_concat招：

SELECT c.id, MAX(o.timestamp) AS "Last, Order", COUNT(o.id) AS "Total Orders", 
     SUM(o.price) AS "Total Spend", 
     substring_index(group_concat(teamname order by o.timestamp desc), ',', 1) as LastTeam 
FROM orders o left outer join 
    customers c ON o.customer = c.id left outer join 
    teams t 
    on o.teamid = t.id 
WHERE o.timestamp > '2012-01-01 00:00:00' 
GROUP BY c.id 
ORDER BY c.id 

Answer 2

試試這個，

SELECT a.ID, 
     a.Name Customer_Name, 
     c.TimeStamp Last_ORDER, 
     c.Name AS Team_Name, 
     COUNT(b.Customer) AS Total_Order, 
     SUM(b.Value) AS Total_Spend 
FROM Customers a 
     INNER JOIN Orders b 
      ON a.ID = b.Customer 
     INNER JOIN 
     (
      SELECT o.Customer, 
        o.TimeStamp, 
        q.Name 
      FROM Orders o 
        INNER JOIN 
        (
         SELECT Customer, MAX(ID) max_ID 
         FROM Orders 
         GROUP BY Customer 
        ) p ON o.Customer = p.Customer AND 
          o.ID = p.max_ID 
        INNER JOIN Team q 
         ON o.Team = q.ID 
     ) c ON a.ID = c.Customer 
GROUP BY a.ID, a.Name 

• SQLFiddle Demo
• SQLFiddle Demo (with date condition)
• SQLFiddle Demo (between dates)

Answer 3

您可以使用類似這樣的查詢：

select c.id, 
    c.name, 
    o1.Last_Order, 
    t.name Team_Name, 
    o3.Total_Orders, 
    o3.Total_Spend 
from customers c 
inner join 
(
    select max(timestamp) Last_Order, 
    max(id) Last_id, 
    customer 
    from orders 
    WHERE timestamp > '2012-01-01 00:00:00' 
    group by customer 
) o1 
    on c.id = o1.customer 
inner join orders o2 
    on c.id = o2.customer 
    and o1.Last_Order = o2.timestamp 
    and o1.Last_id = o2.id 
inner join teams t 
    on o2.team = t.id 
inner join 
(
    select count(team) Total_Orders, 
    sum(value) Total_Spend, 
    customer 
    from orders 
    WHERE timestamp > '2012-01-01 00:00:00' 
    group by customer 
) o3 
    on c.id = o3.customer 
WHERE o2.timestamp > '2012-01-01 00:00:00' 

見SQL Fiddle with Demo