declare @t table ([source] varchar(1),direct varchar(1),mile int)
insert into @t
select 'a','b',20 union all
select 'b','c',10 union all
select 'c','d',15 union all
select 'd','e',10 union all
select 'e','f',5 union all
select 'd','f',15 union all
select 'b','d',20 union all
select 'a','e',10 union all
select 'a','f',15
--sql查詢如下:
;with liang as
select
[source] as [from],direct as [to],mile
from @t
union all
select
direct,[source],mile
from @t
liang2 as
select
[from],[to],
mile as totalmile,
cast('.'+[from]+'.'+[to]+'.' as varchar(max)) as path
from liang
union all
select
a.[from],b.[to],
a.totalmile+b.mile,
cast(a.path+b.[to]+'.' as varchar(max))
from liang2 as a
join liang as b
on case when a.path like '%.'+b.[to]+'.%'
then 1 else 0 end=0
and a.[to]=b.[from]
liang3 as
select
[from],[to],
min(totalmile) as minmile
from liang2
group by [from],[to]
select b.*
from liang3 as a
join liang2 as b
on a.[from]=b.[from]
and a.[to]=b.[to]
and a.minmile=b.totalmile
where a.[from]='a'
and a.[to]='c'
option(maxrecursion 0)
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