同一張表中的MySQL子查詢

Question

我有一張收集客戶付款的表。我想從前3名客戶那裏得到每個客戶的付款。

下面的查詢獲得每個客戶每天每小時的總付款。下面

SELECT 
    hour(received) as hr, 
    login, 
    count(*) as total 
FROM 
    payment 
WHERE 
    received >= date("2011-02-24") 
AND 
    received <date("2011-02-25") 
AND 
    PAYMENT_BATCH_FILE_ID is null 
GROUP BY 
    hr, 
    client_id 
ORDER BY 
    hr, 
    total DESC 

查詢獲得前3名的客戶端爲每一個客戶在一個小時內

SELECT 
    hour(received) as hr, 
    login, 
    count(*) as total 
FROM 
    payment 
WHERE 
    received >=date("2011-02-24") 
AND 
    received < date("2011-02-25") 
AND 
    PAYMENT_BATCH_FILE_ID is null 
AND 
    hour(received)="3" 
GROUP BY 
    hr, 
    client_id 
ORDER BY 
    hr, 
    total DESC 
LIMIT 3 

如何將兩者結合起來的查詢獲得前3名的客戶，使每個小時支付？

謝謝。

Answer 1

這是一個複雜的問題。參考此鏈接http://www.xaprb.com/blog/2006/12/07/how-to-select-the-firstleastmax-row-per-group-in-sql/

祝你好運！