按客户信息汇总子查询和分组

Question

我有三个类似以下的表：

Customer (CustomerID, AddressState)
Account (AccountID, CustomerID, OpenedDate)
Payment (AccountID, Amount)

付款表可以包含一个帐户的多个付款，一个客户可以有多个帐户。

我想做的是按州逐月检索所有付款的总金额。例如

Opened Date| State | Total
--------------------------
2009-01-01 |   CA  | 2,500
2009-01-01 |   GA  | 1,000
2009-01-01 |   NY  |   500
2009-02-01 |   CA  | 1,500
2009-02-01 |   NY  | 2,000

换句话说，我试图找出各州每月支付的费用最多。我只对 OpenedDate 的月份感兴趣，但我将其作为之后处理的日期。我试图在一个查询中检索我需要的所有数据。

我一直在尝试以下方式：

select
  dateadd (month, datediff(month, 0, a.OpenedDate), 0) as 'Date',
  c.AddressState as 'State',
  (
    select sum(x.Amount)
    from (
      select p.Amount
      from Payment p
      where p.AccountID = a.AccountID
    ) as x
  )
  from Account a
  inner join Customer c on c.CustomerID = a.CustomerID
  where ***
  group by
    dateadd(month, datediff(month, 0, a.OpenedDate), 0),
    c.AddressState

where 子句包括 Account 表中的一些常规内容。该查询将不起作用，因为 a.AccountID 未包含在聚合函数中。

我是否以正确的方式处理这个问题？如何检索我需要的数据以计算哪些州的客户支付最多？

Answer 1

如果要按月分组数据，则需要按月分组：

SELECT  AddressState, DATEPART(mm, OpenedDate), SUM(Amount)
FROM    Customer c
INNER JOIN Account a  ON a.CustomerID = c.CustomerID
INNER JOIN Payments p ON p.AccountID = a.AccountID
GROUP BY   AddressState, DATEPART(mm, OpenedDate)

这会向您显示月份编号 (1-12) 和每个州的总金额。请注意，此示例不包括年份：无论年份如何，第 1 个月的所有金额都会相加。如果你愿意，可以添加一个 datepart(yy, OpenedDate)。

Answer 2

换句话说，我试图找出各州每月支付的最高费用

这个会选择每个月最赚钱的州：

SELECT  *
FROM    (
        SELECT  yr, mon, AddressState, amt, ROW_NUMBER() OVER (PARTITION BY yr, mon, addressstate ORDER BY amt DESC) AS rn
        FROM    (
                SELECT  YEAR(OpenedDate) AS yr, MONTH(OpenedDate) AS mon, AddressState, SUM(Amount) AS amt
                FROM    Customer c
                JOIN    Account a
                ON      a.CustomerID = c.CustomerID
                JOIN    Payments p
                ON      p.AccountID = a.AccountID
                GROUP BY
                        YEAR(OpenedDate), MONTH(OpenedDate), AddressState
                )
        ) q
WHERE   rn = 1

将最后一个条件替换为 ORDER BY yr, mon, amt DESC 以获取所有状态的列表，例如您的结果集中：

SELECT  *
FROM    (
        SELECT  yr, mon, AddressState, amt, ROW_NUMBER() OVER (PARTITION BY yr, mon, addressstate ORDER BY amt DESC) AS rn
        FROM    (
                SELECT  YEAR(OpenedDate) AS yr, MONTH(OpenedDate) AS mon, AddressState, SUM(Amount) AS amt
                FROM    Customer c
                JOIN    Account a
                ON      a.CustomerID = c.CustomerID
                JOIN    Payments p
                ON      p.AccountID = a.AccountID
                GROUP BY
                        YEAR(OpenedDate), MONTH(OpenedDate), AddressState
                )
        ) q
ORDER BY
        yr, mon, amt DESC

Answer 3

select
    AddressState,
    year(OpenedDate) as Yr,
    month(OpenedDate) as Mnth,
    sum(Payment) as SumPayment
from Customer c
    inner join Account a
        on c.CustomerID=a.CustomerID
    inner join Payment p
        on a.AccountID=p.AccountID
group by AddressState, month(OpenedDate)