递归 SQL (CTE)

Question

我想编写一个 SQL 查询，其中表具有链接的 OriginalDocket、Docket、DiversionDocket 字段

Declare @DespatchFrom date = '02-01-2021' 

select OriginalDocket, Docket, DiversionDocket 
from trans 
where DespatchDateTime >= @DespatchFrom
and originaldocket <> '' 
and DiversionDocket <> '' 

上面我想写的像

第二张图片的代码：

select t.OriginalDocket, t.Docket, t.DiversionDocket, t2.DiversionDocket as DiversionDocket2
from trans t, trans t2
where t.DespatchDateTime >= @DespatchFrom
and t.originaldocket <> '' 
and t.DiversionDocket <> '' 
and t2.OriginalDocket = t.DiversionDocket
and t2.diversiondocket <> ''

Answer 1

试试这个查询：

select 
    inner.OriginalDocket,
    outer.OriginalDocket, 
    inner.DiversionDocket, 
    outer.DiversionDocket as DiversionDocket2
from
    docketTable as inner
join
    docketTable as outer on inner.Docket = outer.OriginalDocket
where
    inner.DespatchDateTime >= @DespatchFrom
    and inner.originaldocket <> '' 
    and inner.DiversionDocket <> ''