從兩個sql查詢中扣除多行

Question

我創建了一個投注數據庫，我試圖確定誰是最好的和最差的投注者。我立志做最簡單的方法是用戶獲得的獎金之和減去由他們打賭

總和量

我的第一個SQL查詢是

SELECT fromuser,SUM(itemsgiven::int) 
FROM transactions 
WHERE transtype='Bet Placed' 
GROUP BY fromuser 
ORDER BY 2 DESC 

它返回這個

fromuser sum 
15228328 2689 
13896406 2634 
55954103 308 
37460340 64 
66589399 62 

然後我的第二查詢是確定總贏取

SELECT touser,SUM(itemsgiven::float) 
FROM transactions 
WHERE transtype='Bet Won' 
GROUP BY touser 
ORDER BY 2 DESC 

其中r eturns這

touser  sum 
15228328 4387.515 
55954103 152.295 
13896406 120.285 
66589399 71.28 
37460340 56.925 

我的問題是什麼是對這些查詢結合起來，所以我可以有兩列，一個與用戶ID和其他與它們的總獎金（或losings）的最佳方式。我查了一些例子，但是讓我絆倒的部分是你如何確定當你減去只從相同的用戶ID中減去的兩個總和。

編輯：我使用PostgreSQL

Answer 1

您可以使用此查詢：

SELECT usr, SUM(subtotal) AS total 
FROM (
    SELECT fromuser AS usr, SUM(itemsgiven::int) AS subtotal 
    FROM  transactions 
    WHERE transtype='Bet Placed' 
    GROUP BY fromuser 

    UNION ALL 

    SELECT touser AS usr, -1*SUM(itemsgiven::float) AS subtotal 
    FROM  transactions 
    WHERE transtype='Bet Won' 
    GROUP BY touser 
) s 
GROUP BY usr 
ORDER BY 2 DESC 

是y你確定itemsgiven :: int，然後itemsgiven :: float？

Answer 2

你可以用UNION做到這一點：

SELECT user_id, SUM(itemsgiven) as total_itemsgiven 
FROM 
(
    SELECT fromuser user_id, - itemsgiven::int itemsgiven 
    FROM transactions 
    WHERE 'Bet Placed' 
    UNION 
    SELECT touser user_id, itemsgiven::int itemsgiven 
    FROM transactions 
    WHERE 'Bet Won' 

) t 
GROUP BY user_id 
ORDER BY 2 DESC 

Answer 3

您可以使用UNION

SELECT * FROM 
(SELECT fromuser as a,SUM(itemsgiven::numeric) as b 
FROM transactions 
WHERE transtype='Bet Placed' 
GROUP BY fromuser 
UNION 
SELECT touser as a,SUM(itemsgiven::numeric) as b 
FROM transactions 
WHERE transtype='Bet Won' 
GROUP BY touser 
) c 
ORDER BY c.b DESC