使用 SUM 进行递归连接

Question

我有以下格式的数据：

FromStateID ToStateID Seconds
1           2         10
2           3         20
3           4         15
4           5         5

我需要以下输出

FromStateID ToStateID Seconds
1           2         10
2           3         20
3           4         15
4           5         5
1           3         10+20
1           4         10+20+15
1           5         10+20+15+5
2           4         20+15
2           5         20+15+5
3           5         15+5

此输出显示按时间顺序排列的每个组合所花费的总时间 FromStateId 到 ToStateId。

请帮忙。

Answer 1

我认为这是一个遵循链接的递归 CTE：

with cte as (
      select FromStateID, ToStateID, Seconds
      from t
      union all
      select cte.FromStateId, t.ToStateId, cte.Seconds + t.Seconds
      from cte join
           t
           on cte.toStateId = t.FromStateId
     )
select *
from cte;

Here 是一个 db<>fiddle.

Answer 2

@Gordon LinOff 是更好的解决方案。下面是实现相同目的的另一种选择。

您可以使用 CROSS JOIN 和 GROUP BY 实现此目的

DECLARE @table table(FromStateId int, ToStateId int, seconds int)

insert into @table 
values
(1           ,2         ,10),
(2           ,3         ,20),
(3           ,4         ,15),
(4           ,5         ,5 );

;with cte_fromToCombination as
(select f.fromStateId, t.tostateId
from
(select distinct fromStateId from @table) as f
cross join
(select distinct toStateId from @table) as t
)
select c.FromStateId, c.ToStateId, t.sumseconds as Total_seconds 
from cte_fromToCombination as c
CROSS APPLY 
(SELECT sum(t.seconds)
from
@table as t
WHERE t.ToStateId <= c.ToStateId
) as t(sumseconds)
where c.tostateId > c.fromStateId
order by FromStateId,ToStateId



+-------------+-----------+---------------+
| FromStateId | ToStateId | Total_seconds |
+-------------+-----------+---------------+
|           1 |         2 |            10 |
|           1 |         3 |            30 |
|           1 |         4 |            45 |
|           1 |         5 |            50 |
|           2 |         3 |            30 |
|           2 |         4 |            45 |
|           2 |         5 |            50 |
|           3 |         4 |            45 |
|           3 |         5 |            50 |
|           4 |         5 |            50 |
+-------------+-----------+---------------+

使用 SUM 进行递归连接

Recursive join with SUM

sql

tsql

sql-server

common-table-expression