SQL 使用递归 cte 的月结单

Question

我正在尝试根据包含所有历史记录的交易 table 创建月度银行账户对帐单。我希望将期初余额作为第一行，然后使用递归 cte 将当前月份的交易与当时更新的余额进行交易。我知道这也可以通过 table 更新来完成，但我正在寻找递归。

table 结构如下：

declare @temp table (date datetime,tran_id int,cust_id int,tran_type char,amount int)
insert into @temp values('2017-06-06 22:05:10.703',1,1,'c',700),
('2017-06-12 22:05:10.703',2,1,'d',100),('2017-06-20 22:05:10.703',3,1,'c',200),
('2017-06-26 22:05:10.703',4,1,'d',450),(getdate()+1,5,1,'d',200),
(getdate()+2,6,1,'d',200),(getdate()+3,7,1,'c',500),
(getdate()+4,8,1,'d',300),(getdate()+5,9,1,'d',200),
('2017-06-18 22:05:10.703',12,1,'d',100)

这里有第 6 个月和第 7 个月的交易。当月的期初余额将是 6 月份所有交易的总和，它将用作获得递归余额的锚点。现在我希望 select 查询有日期，tran_id，cust_id，贷方，借方，余额作为结果集。

所以如果 table 有这样的数据：

date                   tran_id  cust_id tran_type   amount
2017-06-06 22:05:10.703 1   1   c   700
2017-06-12 22:05:10.703 2   1   d   100
2017-06-20 22:05:10.703 3   1   c   200
2017-06-26 22:05:10.703 4   1   d   450
2017-07-08 16:34:24.817 5   1   d   200
2017-07-09 16:34:24.817 6   1   d   200
2017-07-10 16:34:24.817 7   1   c   500
2017-07-11 16:34:24.817 8   1   d   300
2017-07-12 16:34:24.817 9   1   d   200
2017-06-18 22:05:10.703 12  1   d   100

The monthly statement for month 7 should be like:
opening balance of 250

date                     tran_id    cust_id credit  debit   balance
2017-07-08 16:40:56.810     5        1      NULL     200    50
2017-07-09 16:40:56.810     6        1      NULL     200    -150
2017-07-10 16:40:56.810     7        1      500      NULL   350
2017-07-11 16:40:56.810     8        1      NULL     300    -50
2017-07-12 16:40:56.810     9        1      NULL     200    -250

我尝试过使用递归 cte 和窗口求和函数，但它并不能提供连续的平衡，只是逐行平衡。

在 cte 中使用聚合函数也是不行的。

;with cte as
(
select cust_id,sum(case when tran_type='c' then amount*1 else amount*-1 end) 
as 'opening balance' from @temp 
where MONTH(date)=6 group by cust_id
),

cte2 as
(
select * from cte
union all
select t.cust_id,amount+[opening balance] as 'balance1' from @temp t join 
cte2 c on c.cust_id=t.cust_id
where MONTH(date)=7
)
select * from cte2

或

;with cte as
(
select cust_id,sum(case when tran_type='c' then amount*1 else amount*-1 end) 
as 'opening balance' from @temp 
where MONTH(date)=6 group by cust_id
union all
select t.cust_id,SUM(amount+[opening balance]) as 'balance1' from @temp t 
join cte c on c.cust_id=t.cust_id
where MONTH(date)=7
)
select * from cte
option (MAXRECURSION 1000)

我错过了什么？

Answer 1

只需使用累计和：

select t.*,
       sum(case when tran_type = 'c' then amount else - amount end) over 
           (partition by cust_id order by date) as balance
from @temp t;

然后您可以 select 使用子查询或 CTE 的范围：

select t.*
from (select t.*,
             sum(case when tran_type = 'c' then amount else - amount end) over 
                 (partition by cust_id order by date) as balance
      from @temp t
     ) t
where . . .

您需要 where 的子查询，因此它不会影响累计总和。

编辑：

在SQL Server 2008中，您可以使用cross apply:

select t.*,
       t2.balance
from @temp t cross apply
     (select sum(case when t2.tran_type = 'c' then t2.amount else - t2.amount end) as balance
      from @temp t2
      where t2.cust_id = t.cust_id and t2.date <= t.date
     ) t2;

Answer 2

对于旧版本，您可以使用 CROSS APPLY 来计算运行余额

;WITH opening_balance_cte
     AS (SELECT cust_id,
                Sum(CASE WHEN tran_type = 'c' THEN amount ELSE -amount END) AS opening_balance
         FROM   Yourtable
         WHERE  [date] < '2017-07-01'
         GROUP  BY cust_id)
SELECT *,
       balance
FROM   Yourtable a
       JOIN opening_balance_cte ob
         ON ob.cust_id = a.cust_id
       CROSS apply (SELECT ob.opening_balance + Sum(CASE WHEN tran_type = 'c' THEN amount ELSE -amount END) AS balance
                    FROM   Yourtable b
                    WHERE  a.cust_id = b.cust_id
                           AND a.tran_id >= b.tran_id
                           AND b.[date] >= '2017-07-01'
                           AND b.[date] < '2017-08-01') cs
WHERE  a.[date] >= '2017-07-01'
       AND a.[date] < '2017-08-01'

如果您真的想知道如何使用 Recursive CTE 实现此目的，那么

;WITH opening_balance_cte
     AS (SELECT cust_id,
                Sum(CASE WHEN tran_type = 'c' THEN amount ELSE -amount END) AS opening_balance
         FROM   @temp
         WHERE  [date] < '2017-07-01'
         GROUP  BY cust_id),
     rec_cte
     AS (SELECT TOP 1 a.*,
                      opening_balance + CASE WHEN tran_type = 'c' THEN amount ELSE -amount END AS balance
         FROM   @temp a
                JOIN opening_balance_cte o
                  ON a.cust_id = o.cust_id
         WHERE  a.[date] >= '2017-07-01'
                AND a.[date] < '2017-08-01'
         ORDER  BY a.[date] ASC
         UNION ALL
         SELECT t.*,
                rc.balance + CASE WHEN t.tran_type = 'c' THEN t.amount ELSE -t.amount END
         FROM   rec_cte rc
                JOIN @temp t
                  ON t.cust_id = rc.cust_id
                     AND t.tran_id = rc.tran_id + 1)
SELECT *
FROM   rec_cte

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