SQL Oracle/聚合查询

Question

我正在尝试在 Oracle 上运行查询。我有一个账户的已结算付款表，我有一个查询，其中包含最后三个已结算金额以及任何已注销的金额，用于我需要此信息的任何帐户。

但是，有些帐户是按周计算的，对于这些帐户，我想将他们的每周结算汇总到他们的每月组中。这是我到目前为止的代码：

SELECT   *
FROM     (
    SELECT *
    FROM   (
            SELECT   gwod.account_id,
                     gwod.charge_period_start,
                     SUM(gwod.total_due_on_charge) total_due_on_charge,
                     SUM(gwod.amount_written_off) amount_written_off,
                     DENSE_RANK() over (PARTITION BY gwod.account_id 
                                        ORDER BY charge_period_start DESC) rownumber
            FROM     report.accounts_write_off gwod
            WHERE    account_id IN (‘account_number’)
            GROUP BY gwod.account_id,
                     gwod.charge_period_start
            HAVING   SUM (gwod.total_due_on_charge) <> 0) t1
    WHERE  t1.rownumber <=3) 
    PIVOT (MAX(charge_period_start) charge_period, 
           MAX(total_due_on_charge) total_due_on_charge, 
           MAX(amount_written_off) amount_written_off 
           FOR rownumber IN (1,2,3))
ORDER BY account_id.* 

这非常有效，但对于基于每周的帐户，所以与其提取最后三个已结算的每周金额，即 25-09-17、18-09-17、11-09-2017，我想要以提取 9 月、8 月和 7 月的总付款。

我希望这一切都有意义。

Answer 1

使用内部查询的SELECT 和GROUP BY 以及PARTITION 和PIVOT 子句中的EXTRACT(month ...) 将聚合从当前单位级别（即每周）更改为月级别：

SELECT   *
FROM     (
    SELECT *
    FROM   (
            SELECT   gwod.account_id,
                     EXTRACT(month FROM gwod.charge_period_start) charge_period_month,
                     SUM(gwod.total_due_on_charge) total_due_on_charge,
                     SUM(gwod.amount_written_off) amount_written_off,
                     DENSE_RANK() over (PARTITION BY gwod.account_id 
                                        ORDER BY EXTRACT(month FROM gwod.charge_period_start) DESC) rownumber
            FROM     report.accounts_write_off gwod
            WHERE    account_id IN ('account_number')
            GROUP BY gwod.account_id,
                     EXTRACT(month FROM gwod.charge_period_start)
            HAVING   SUM (gwod.total_due_on_charge) <> 0) t1
    WHERE  t1.rownumber <=3) 
    PIVOT (MAX(charge_period_month) charge_period, 
           MAX(total_due_on_charge) total_due_on_charge, 
           MAX(amount_written_off) amount_written_off 
           FOR rownumber IN (1,2,3))
ORDER BY account_id.* 

DEMO （随机数据）：

http://rextester.com/UJK84858