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问题描述
我正在尝试根据同一表中的 ProductID 在新列中获取现金"、支票"和信用卡"总计.
I'm trying to get 'Cash', 'Check' and 'Credit Card' totals in new columns based on ProductID from the same table.
表格 - 付款
+-----------+------------+---------------+--------+
| ProductID | SaleDate | PaymentMethod | Amount |
+-----------+------------+---------------+--------+
| 3 | 2012-02-10 | Cash | 10 |
| 3 | 2012-02-10 | Cash | 10 |
| 3 | 2012-02-10 | Check | 15 |
| 3 | 2012-02-10 | Credit Card | 25 |
| 4 | 2012-02-10 | Cash | 5 |
| 4 | 2012-02-10 | Check | 6 |
| 4 | 2012-02-10 | Credit Card | 7 |
+-----------+------------+---------------+--------+
期望的输出 -
+------------+------+-------+-------------+-------+
| ProductID | Cash | Check | Credit Card | Total |
+------------+------+-------+-------------+-------+
| 3 | 20 | 15 | 25 | 60 |
| 4 | 5 | 6 | 7 | 18 |
+------------+------+-------+-------------+-------+
我试过 LEFT JOINing 同一张桌子，但没有任何成功.任何建议，将不胜感激.谢谢.
I've tried LEFT JOINing the same table but haven't had any success. Any suggestions would be appreciated. Thanks.
不成功且不完整的尝试 -
Unsuccessful and incomplete attempt -
SELECT P.ProductID, Sum( PCash.Amount ) AS 'Cash', SUM( PCheck.Amount ) AS 'Check', SUM( PCredit.Amount) AS 'Credit Card'
FROM Payments AS P
LEFT JOIN Payments AS PCash ON P.ProductID = PCash.ProductID AND PCash.PaymentMethod = 'Cash'
LEFT JOIN Payments AS PCheck ON P.ProductID = PCheck.ProductID AND PCheck.PaymentMethod = 'Check'
LEFT JOIN Payments AS PCredit ON P.ProductID = PCredit.ProductID AND PCredit.PaymentMethod = 'Credit'
WHERE P.SaleDate = '2012-02-10' GROUP BY ProductID;
推荐答案
我认为你让这件事变得比需要的更复杂.
I think you're making this a bit more complicated than it needs to be.
SELECT
ProductID,
SUM(IF(PaymentMethod = 'Cash', Amount, 0)) AS 'Cash',
-- snip
SUM(Amount) AS Total
FROM
Payments
WHERE
SaleDate = '2012-02-10'
GROUP BY
ProductID
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