Tsql 迭代CTE求解

我一直在开发一个CTE，它可以根据一些工作项目有效地创建发票行。鉴于：

Create table JobLines (line int, code varchar(10), qty decimal(9,2))  
go

insert into JobLines values (1, '2222A', 1)  
insert into JobLines values (2, '2222B', 3)  
insert into JobLines values (3, '2222A', -1)  
insert into JobLines values (4, '2222C', 2)  
insert into JobLines values (5, '2222D', 1)  
insert into JobLines values (6, '2222B', -1)  
insert into JobLines values (7, '2222A', 2)  
insert into JobLines values (8, '2222B', -1)  
insert into JobLines values (9,'2222A', -1)  
go

我想要一台CTE，它可以： 在与代码匹配之前，从正行减去每一个负行

结果应该是： 第1行-0减去第3行。 第2行-1减去第6行和第8行。 第4行-无变化。 第5行-无变化。 第7行-1减去第9行

有几次我差一点就到了。主要的问题是，我无法得到第2行或第7行所需的结果，因为我无法有效地将需要减去的2行组合在一起

我的方法是尝试在正行上迭代，获取每行的负行

我正在处理的示例代码：

;with cte_positive_rows as (select line, code, qty
    ,row_number() over (partition by code order by line) code_instance
    ,row_number() over (order by line) row_sequence
from jobLines
where qty > 0
)
,cte_negative_rows as (
    select line, code, qty
    ,row_number() over (partition by code order by line) code_instance
    ,row_number() over (order by line) row_sequence
from jobLines
where qty < 0
)
,cte_iterator as(
--base case - start with line 1 from cte_postive_rows...

select min(base.line) line, base.code
    ,cast(sum(base.qty + neg.qty) as     decimal(9,2)) total_qty
    ,base.code_instance
    ,base.row_sequence, base.row_sequence + 1 as next_row
    from cte_positive_rows base
    inner join cte_negative_rows neg
    on
    neg.row_sequence = base.row_sequence
    and neg.code_instance = base.code_instance
    where base.row_sequence = 1
    group by base.code, base.code_instance, base.row_sequence

    union all

    --iterative case - each line..
    -- the iterative case should returns all the rows that needed modifying

    select row.line, row.code
    ,cast(row.qty + neg.qty as decimal(9,2)) qty, row.code_instance
    ,row.row_sequence
    ,row.row_sequence + 1 as next_row
    from cte_positive_rows row 
    inner join cte_negative_rows neg
    on
    neg.row_sequence = row.row_sequence
    and neg.code_instance = row.code_instance
    inner join cte_iterator cte
    on row.row_sequence = cte.next_row
)

-- get all the modified and non-modifed rows with joins

select pos.line, pos.code, pos.qty, pos.code_instance, pos.row_sequence
from cte_positive_rows pos
left outer join cte_iterator i
on pos.row_sequence = i.row_sequence
where i.row_sequence IS NULL
union all 
select line, code, total_qty, code_instance, row_sequence from cte_iterator
order by row_sequence

---

我的梦想可能吗

我不确定我是否完全理解您的需求，但这似乎满足了您的需求：

select line, code, qty + isnull((
    -- get the sum of all negative values...
    select sum(j1.qty)
    from JobLines j1
    where 
        -- ...for the same code, but with a higher line number...
        j1.code = PositiveLines.code and 
        j1.line > PositiveLines.line and 
        j1.qty < 0 and
        -- ...where there is no positive value on a previous line
        not exists (
            select * 
            from JobLines
            where 
                code = j1.code and 
                qty > 0 and 
                line > j1.line)
    ),0)
from
(   
select
    line, code, qty
from
    JobLines
where
    qty > 0
) PositiveLines

---

也许我需要以某种方式使用交叉应用来正确地为负行设置关键帧，但更复杂的是。可能有教育意义。谢谢，我来看看。您能找到一种方法使code_实例在负行上作为更好的键执行吗？非常好，谢谢。我被CTE追得太多了。。在这种情况下，工作的工具似乎是错误的。对于学习来说，看到它以这种方式实现仍然是很好的，但这非常有效-不能与结果争论！比我决定走的路简单得多：该死——回到这里，它只适用于问题数据。如果引入第10行，或删除第9行，则该行不起作用

1   2222A   0.00    1   1
2   2222B   2.00    1   2
4   2222C   2.00    1   3
5   2222D   1.00    1   4
7   2222A   2.00    2   5

select line, code, qty + isnull((
    -- get the sum of all negative values...
    select sum(j1.qty)
    from JobLines j1
    where 
        -- ...for the same code, but with a higher line number...
        j1.code = PositiveLines.code and 
        j1.line > PositiveLines.line and 
        j1.qty < 0 and
        -- ...where there is no positive value on a previous line
        not exists (
            select * 
            from JobLines
            where 
                code = j1.code and 
                qty > 0 and 
                line > j1.line)
    ),0)
from
(   
select
    line, code, qty
from
    JobLines
where
    qty > 0
) PositiveLines