Question

我在发票和信用卡交易之间存在多对多的关系，我试图将这些交易映射到一起。思考问题的最佳方法是将TransactionInvoiceMap想象为二分图。对于每个连接的子图，找到所有发票的总和以及该子图中所有交易的总和。在我的查询中，我想返回为每个子图计算的值以及它们与之关联的事务ID。相关交易的总数应该相同。

更明确地，给出以下交易/发票

Table: TransactionInvoiceMap
TransactionID  InvoiceID
1              1
2              2
3              2
3              3

Table: Transactions
TransactionID  Amount
1              $100
2              $75
3              $75

Table: Invoices
InvoiceID  Amount
1          $100
2          $100
3          $50

我想要的输出是

TransactionID  TotalAsscTransactions TotalAsscInvoiced
1              $100                  $100
2              $150                  $150
3              $150                  $150

请注意，发票2和3以及交易2和3是逻辑组的一部分。

这是一个显然有效的解决方案（简化，名称已更改），但速度很慢。我很难弄清楚如何优化它，但我认为这将涉及将子查询消除到TransactionInvoiceGrouping中。随意提出截然不同的东西。

with TransactionInvoiceGrouping as (
    select 
        -- Need an identifier for each logical group of transactions/invoices, use
        -- one of the transaction ids for this.
        m.TransactionID,
        m.InvoiceID,
        min(m.TransactionID) over (partition by m.InvoiceID) as GroupingID
    from TransactionInvoiceMap m
)
select distinct
    g.TransactionID,
    istat.InvoiceSum as TotalAsscInvoiced,
    tstat.TransactionSum as TotalAsscTransactions
from TransactionInvoiceGrouping g
    cross apply (
        select sum(ii.Amount) as InvoiceSum
        from (select distinct InvoiceID, GroupingID from TransactionInvoiceGrouping) ig
            inner join Invoices ii on ig.InvoiceID = ii.InvoiceID
        where ig.GroupingID = g.GroupingID
    ) as istat
    cross apply (
        select sum(it.Amount) as TransactionSum
        from (select distinct TransactionID, GroupingID from TransactionInvoiceGrouping) ig
            left join Transactions it on ig.TransactionID = it.TransactionID
        where ig.GroupingID = g.GroupingID
        having sum(it.Amount) > 0
    ) as tstat

Answer 1

我已在recursive CTE中实施了解决方案：

;with TranGroup as (
    select TransactionID
        , InvoiceID as NextInvoice
        , TransactionID as RelatedTransaction
        , cast(TransactionID as varchar(8000)) as TransactionChain
    from TransactionInvoiceMap
    union all
    select g.TransactionID
        , m1.InvoiceID
        , m.TransactionID
        , g.TransactionChain + ',' + cast(m.TransactionID as varchar(11))
    from TranGroup g
        join TransactionInvoiceMap m on g.NextInvoice = m.InvoiceID
        join TransactionInvoiceMap m1 on m.TransactionID = m1.TransactionID
    where ',' + g.TransactionChain + ',' not like '%,' + cast(m.TransactionID as varchar(11)) + ',%'
)
, RelatedTrans as (
    select distinct TransactionID, RelatedTransaction
    from TranGroup
)
, RelatedInv as (
    select distinct TransactionID, NextInvoice as RelatedInvoice
    from TranGroup
)
select TransactionID
    , (
        select sum(Amount)
        from Transactions
        where TransactionID in (
            select RelatedTransaction
            from RelatedTrans
            where TransactionID = t.TransactionID
        )
    ) as TotalAsscTransactions
    , (
        select sum(Amount)
        from Invoices
        where InvoiceID in (
            select RelatedInvoice
            from RelatedInv
            where TransactionID = t.TransactionID
        )
    ) as TotalAsscInvoiced
from Transactions t

可能还有一些优化空间（包括我的对象命名！）但我相信我至少有一个正确的解决方案，它将收集所有可能的交易 - 发票关系以包含在计算中。

我无法在此页面上获得现有解决方案以提供OP所需的输出，并且随着我添加更多测试数据，它们变得更加丑陋。我不确定OP发布的“慢”解决方案是否正确如上所述。我很可能误解了这个问题。

其他信息：

我经常看到，在处理大量数据时，递归查询可能会很慢。也许这可能是另一个SO问题的主题。如果是这种情况，那么在SQL端尝试的东西可能是限制范围（添加where子句），索引基表，首先选择CTE到临时表，索引那个临时表，想一想更好停止CTE的条件......当然，首先是个人资料。

Answer 2

如果我理解正确的问题，我认为您正在尝试为每张发票找到最低的交易ID，并且我已使用排名功能来执行相同的操作。

WITH TransactionInvoiceGrouping AS (
SELECT 
    -- Need an identifier for each logical group of transactions/invoices, use
    -- one of the transaction ids for this.
    m.TransactionID,
    m.InvoiceID,       
    ROW_NUMBER() OVER (PARTITION BY m.InvoiceID ORDER BY m.TransactionID ) AS recno
FROM TransactionInvoiceMap m
)
 SELECT 
g.TransactionID,
istat.InvoiceSum AS TotalAsscInvoiced,
tstat.TransactionSum AS TotalAsscTransactions
 FROM TransactionInvoiceGrouping g
CROSS APPLY(
    SELECT SUM(ii.Amount) AS InvoiceSum
    FROM TransactionInvoiceGrouping ig
        inner JOIN Invoices ii ON ig.InvoiceID = ii.InvoiceID
    WHERE ig.TransactionID = g.TransactionID
    AND ig.recno = 1
) AS istat
CROSS APPLY(
    SELECT sum(it.Amount) AS TransactionSum
    FROM TransactionInvoiceGrouping ig
        LEFT JOIN transactions it ON ig.TransactionID = it.TransactionID
    WHERE ig.TransactionID = g.TransactionID
    AND ig.recno = 1
    HAVING SUM(it.Amount) > 0
) AS tstat

WHERE g.recno = 1

如何在多对多映射表中有效地创建逻辑数据子集？

2 个答案: