连接三个表并从列数据中减去列的总和

Question

我有三张表accounts ， receivables和receives 。

我的基本表是应收账款我想从账户表中获取名称，然后从具有相同参考号的应收账款表中的应收账款列中减去接收表中收到的列的总和。 如果余额为零，我想忽略。

帐户

ID	姓名
22	约翰
23	卡恩
24	法利斯
25	哈塞尼
26	根特

应收账款

ID	应收款	参考
22	70	A1
24	100	A2
26	60	A3
24	15	A4

收到

参考	ID	已收到
A1	22	30
A2	24	60
A1	22	40
A3	26	20
A2	24	10

期望的结果

ID	姓名	参考	应收款	已收到	平衡	total_id_balance
24	法利斯	A2	100	70	30	45
26	根特	A3	60	20	40	40
24	法利斯	A4	15	0	15	45

我试过这段代码，但它对我不起作用

SELECT * 
FROM receivables AS rvb 
  LEFT JOIN accounts AS acc 
    ON rvb.id = acc.id 
  LEFT JOIN (SELECT SUM(received) as sum_rvd FROM receiveds) AS rvd 
    ON acc.id = rvd.id where rvb.receivable>rvd.sum_rvd

Answer 1

INNER JOIN过滤掉 NULL 值， HAVING子句删除零余额行。

SELECT 
    accounts.* ,
    ra.receivable,
    rd.received,
    ra.receivable - rd.received as balance
FROM accounts
    INNER JOIN ( SELECT id, SUM(receivable) as receivable FROM receivables GROUP BY id ) ra 
        ON ra.id = accounts.id
    INNER JOIN ( SELECT id, SUM(received) as received FROM receiveds GROUP BY id ) rd 
        ON rd.id = accounts.id
HAVING balance > 0

更新

使用ref字段，我们只需要将其添加为子选择的另一个分组字段，并将第二个INNER JOIN更改为LEFT JOIN （实际上看起来从一开始就是一个错误，因为我们错过了没有receiveds但仍然有正余额的条目）。 还将received字段更改为COALESCE以获得零而不是 NULL（表示receiveds表中不存在的行）。 由于您需要一个整体的 per-id total_id_balance字段，因此获取它的自然方法是使用window functions 。 请注意，它们仅支持 MySQL 8.0+。 因此，生成的查询如下所示：

SELECT 
    accounts.* ,
    ra.ref,
    ra.receivable,
    COALESCE(rd.received, 0) as received,
    ra.receivable - COALESCE(rd.received, 0) as balance,
    SUM( ra.receivable - COALESCE(rd.received, 0) ) OVER ( PARTITION BY id ) as total_id_balance
FROM accounts
    INNER JOIN ( SELECT id, SUM(receivable) as receivable, ref FROM receivables GROUP BY id, ref ) ra 
        ON ra.id = accounts.id
    LEFT JOIN ( SELECT id, SUM(received) as received, ref FROM receiveds GROUP BY id, ref ) rd 
        ON 
            rd.id = accounts.id 
            AND 
            ra.ref = rd.ref
HAVING balance > 0
ORDER BY ref

Answer 2

这对我有用 -

编辑-在receivables中添加对非唯一 ID 的支持

SELECT acc.id ,acc.name, res.receivable, res.received, (res.receivable - res.received) AS balance
FROM accounts AS acc JOIN 
    (SELECT recv.id, recv.receivable, rec.received 
     FROM (
         SELECT id, SUM(receivable) AS receivable
         FROM receivables
         GROUP BY id) AS recv JOIN 
            (SELECT id, SUM(received) AS received 
             FROM receiveds 
             GROUP BY id) AS rec ON rec.id = recv.id 
         WHERE rec.received < recv.receivable) AS res ON res.id = acc.id;

Answer 3

假设在 receivables 中可能有一个 id 而在 receiveds 中没有相应的 id，则第二个连接需要是 LEFT JOIN 并且您需要处理 SELECT 列表中的 NULL -

SELECT 
    a.*,
    ra.receivable,
    IFNULL(rd.received, 0) received,
    ra.receivable - IFNULL(rd.received, 0) balance
FROM accounts a
INNER JOIN (
    SELECT id, SUM(receivable) receivable
    FROM receivables
    GROUP BY id
) ra 
    ON a.id = ra.id
LEFT JOIN (
    SELECT id, SUM(received) received
    FROM receiveds
    GROUP BY id
) rd 
    ON a.id = rd.id
HAVING balance > 0;

您可以（并且应该）更进一步并删除第一个派生表，因为它是不必要的开销 -

SELECT
    a.*,
    SUM(ra.receivable) receivable,
    IFNULL(SUM(rd.received), 0) received,
    SUM(ra.receivable) - IFNULL(rd.received, 0) balance
FROM accounts a
INNER JOIN receivables ra
    ON a.id = ra.id
LEFT JOIN (
    SELECT id, SUM(received) received
    FROM receiveds
    GROUP BY id
) rd
    ON a.id = rd.id
GROUP BY id
HAVING balance > 0;

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