How to get the deepest levels of a hierarchical sql query - sql

Question

I'm using SQLServer 2008.
Say I have a recursive hierarchy table, SalesRegion, whit SalesRegionId and ParentSalesRegionId. What I need is, given a specific SalesRegion (anywhere in the hierarchy), retrieve ALL the records at the BOTTOM level.
I.E.:
SalesRegion, ParentSalesRegionId
1, null
1-1, 1
1-2, 1
1-1-1, 1-1
1-1-2, 1-1
1-2-1, 1-2
1-2-2, 1-2
1-1-1-1, 1-1-1
1-1-1-2, 1-1-1
1-1-2-1, 1-1-2
1-2-1-1, 1-2-1
(in my table I have sequencial numbers, this dashed numbers are only to be clear)
So, if the user enters 1-1, I need to retrieve al records with SalesRegion 1-1-1-1 or 1-1-1-2 or 1-1-2-1 (and NOT 1-2-2). Similarly, if the user enters 1-1-2-1, I need to retrieve just 1-1-2-1
I have a CTE query that retrieves everything below 1-1, but that includes rows that I don't want:
WITH SaleLocale_CTE AS (
SELECT SL.SaleLocaleId, SL.SaleLocaleName, SL.AccountingLocationID, SL.LocaleTypeId, SL.ParentSaleLocaleId, 1 AS Level /*Added as a workaround*/
FROM SaleLocale SL
WHERE SL.Deleted = 0
AND (#SaleLocaleId IS NULL OR SaleLocaleId = #SaleLocaleId)
UNION ALL
SELECT SL.SaleLocaleId, SL.SaleLocaleName, SL.AccountingLocationID, SL.LocaleTypeId, SL.ParentSaleLocaleId, Level + 1 AS Level
FROM SaleLocale SL
INNER JOIN SaleLocale_CTE SLCTE ON SLCTE.SaleLocaleId = SL.ParentSaleLocaleId
WHERE SL.Deleted = 0
)
SELECT *
FROM SaleLocale_CTE
Thanks in advance!
Alejandro.

Answer 1

I found a quick way to do this, but I'd rather the answer to be in a single query. So if you can think of one, please share! If I like it better, I'll vote for it as the best answer.
I added a "Level" column in my previous query (I'll edit the question so this answer is clear), and used it to get the last level and then delete the ones I don't need.
INSERT INTO #SaleLocales
SELECT *
FROM SaleLocale_GetChilds(#SaleLocaleId)
SELECT #LowestLevel = MAX(Level)
FROM #SaleLocales
DELETE #SaleLocales
WHERE Level <> #LowestLevel

Answer 2

Building off your post:
; WITH CTE AS
(
SELECT *
FROM SaleLocale_GetChilds(#SaleLocaleId)
)
SELECT
FROM CTE a
JOIN
(
SELECT MAX(level) AS level
FROM CTE
) b
ON a.level = b.level
There were a few edits in there. Kept hitting post...

Answer 3

Are you looking for something like this:
declare #SalesRegion as table ( SalesRegion int, ParentSalesRegionId int )
insert into #SalesRegion ( SalesRegion, ParentSalesRegionId ) values
( 1, NULL ), ( 2, 1 ), ( 3, 1 ),
( 4, 3 ), ( 5, 3 ),
( 6, 5 )
; with CTE as (
-- Get the root(s).
select SalesRegion, CAST( SalesRegion as varchar(1024) ) as Path
from #SalesRegion
where ParentSalesRegionId is NULL
union all
-- Add the children one level at a time.
select SR.SalesRegion, CAST( CTE.Path + '-' + cast( SR.SalesRegion as varchar(10) ) as varchar(1024) )
from CTE inner join
#SalesRegion as SR on SR.ParentSalesRegionId = CTE.SalesRegion
)
select *
from CTE
where Path like '1-3%'

Answer 4

I haven't tried this on a serious dataset, so I'm not sure how it'll perform, but I believe it solves your problem:
WITH SaleLocale_CTE AS (
SELECT SL.SaleLocaleId, SL.SaleLocaleName, SL.AccountingLocationID, SL.LocaleTypeId, SL.ParentSaleLocaleId, CASE WHEN EXISTS (SELECT 1 FROM SaleLocal SL2 WHERE SL2.ParentSaleLocaleId = SL.SaleLocaleID) THEN 1 ELSE 0 END as HasChildren
FROM SaleLocale SL
WHERE SL.Deleted = 0
AND (#SaleLocaleId IS NULL OR SaleLocaleId = #SaleLocaleId)
UNION ALL
SELECT SL.SaleLocaleId, SL.SaleLocaleName, SL.AccountingLocationID, SL.LocaleTypeId, SL.ParentSaleLocaleId, CASE WHEN EXISTS (SELECT 1 FROM SaleLocal SL2 WHERE SL2.ParentSaleLocaleId = SL.SaleLocaleID) THEN 1 ELSE 0 END as HasChildren
FROM SaleLocale SL
INNER JOIN SaleLocale_CTE SLCTE ON SLCTE.SaleLocaleId = SL.ParentSaleLocaleId
WHERE SL.Deleted = 0
)
SELECT *
FROM SaleLocale_CTE
WHERE HasChildren = 0