SQL Server以特定格式显示数据树

Question

我们有一个这样的表（简化版）：

产品：

Itemid   Itemname    Itemfatherid
itemA    theitemA    null
itemB    theitemB    null
itemC    theitemC    itemA
itemD    theitemD    itemA
itemE    theitemE    itemC
itemF    theitemF    itemE
itemG    theitemG    itemD

我们需要一个sql查询，它提供以下结果/格式:(更正版本）

Col1    Col2    Col3    Col4
itemA   itemC   itemE   itemF
itemA   itemD   itemG   NULL
itemB   NULL    NULL    NULL

我们的ERP会采用这种结果并将其转换为这样的树形控件：

-itemA
    -itemC
        -itemE
            itemF
    -itemD
        itemG
itemB

树的级别不固定，因此列数必须是动态的......

CTE有一些方法，但我们还没有达到解决方案：S

http://www.sqlservercurry.com/2009/06/simple-family-tree-query-using.html

此外，我们需要知道树的深度（将其传递给GridControl ...）在此示例中它将为3（它需要最大父级别数 - > -itemA -itemC -itemE ）

Answer 1

样本表

create table so1 (Itemid varchar(100), Itemname varchar(100), Itemfatherid varchar(100))
insert so1 select
'itemA','theitemA',null union all select
'itemB','theitemB',null union all select
'itemC','theitemC','itemA' union all select
'itemD','theitemD','itemA' union all select
'itemE','theitemE','itemC' union all select
'itemF','theitemF','itemE' union all select
'itemG','theitemG','itemD'

查询

if OBJECT_ID('tempdb..#tmp') is not null drop table #tmp
;
create table #tmp (
    uniqueid uniqueidentifier not null,
    level int not null,
    itemid varchar(100) null,
    primary key clustered(uniqueid, level)
)
;with cte(level, itemid, parentid, uniqueid) as
(
    select 1, itemid, itemfatherid, NEWID()
    from so1
    where not exists (select * from so1 k where k.itemfatherid=so1.itemid)
    union all
    select cte.level+1, t.itemid, t.itemfatherid, cte.uniqueid
    from cte
    inner join so1 t on t.Itemid = cte.parentid
)
insert #tmp (uniqueid, level, itemid)
select uniqueid, level, itemid
from cte
option (maxrecursion 1000) -- as required
;
;with tmp as (
    select *, newlevel = ROW_NUMBER() over (partition by uniqueid order by level desc)
    from #tmp)
update tmp
set level = newlevel
;
declare @sql nvarchar(max), @columns nvarchar(max)
;
set @sql = CONVERT(nvarchar(max), (
    select number [data()]
    from master..spt_values
    where type='P' and number between 1 and (select MAX(level) from #tmp)
    order by 1
    for xml path('a')))
select @sql = stuff(replace(replace(@sql,'</a><a>','],['),'</a>',']'),1,3,'[')
select @sql = '
select ' + @sql + '
from #tmp
pivot (max(itemid) for level in (' + @sql + ')) v
order by ' + @sql
exec (@sql)

输出

1       2       3       4
itemA   itemC   itemE   itemF
itemA   itemD   itemG   NULL
itemB   NULL    NULL    NULL