I would like to query hierarchy results ordered by depth first without the use of SQL's heiarchyid built in function. Essentially, I am hoping to accomplish the depth ordering without any fancy functions.
I have provided a temp table below that contains these records:
Id
p_Id
order1
name1
1
null
1
josh
2
null
2
mary
3
null
3
george
4
1
1
joe
5
1
2
jeff
6
2
1
marg
7
2
2
moore
8
2
3
max
9
3
1
gal
10
3
2
guy
11
4
1
tod
12
4
2
ava
13
9
1
ron
14
9
2
bill
15
9
100
pat
where p_Id is the id of the parent record, and order1 is essentially just the ordering of which the depth first output should be displayed. To show why my query does not fully work, I made the order1 of the last record 100 instead of say, 3. However this should not ultimately matter since 100 and 3 both come after the previous order1 value, 2.
An example of a correct result table is shown below:
Id
p_Id
order1
name1
Descendants
1
null
1
josh
josh
4
1
1
joe
josh/joe
11
4
1
tod
josh/joe/tod
12
4
2
ava
josh/joe/ava
5
1
2
jeff
josh/jeff
2
null
2
mary
mary
6
2
1
marg
mary/marg
7
2
2
moore
mary/moore
8
2
3
max
mary/max
3
null
3
george
george
9
3
1
gal
george/gal
13
9
1
ron
george/gal/ron
15
9
2
bill
george/gal/bill
14
9
100
pat
george/gal/pat
10
3
2
guy
george/guy
Where an example of my results are shown below:
Id
p_Id
order1
name1
Descendants
levels
1
null
1
josh
josh
.1
4
1
1
joe
josh/joe
.1.1
11
4
1
tod
josh/joe/tod
.1.1.1
12
4
2
ava
josh/joe/ava
.1.1.2
5
1
2
jeff
josh/jeff
.1.2
2
null
2
mary
mary
.2
6
2
1
marg
mary/marg
.2.1
7
2
2
moore
mary/moore
.2.2
8
2
3
max
mary/max
.2.3
3
null
3
george
george
.3
9
3
1
gal
george/gal
.3.1
13
9
1
ron
george/gal/ron
.3.1.1
15
9
100
pat
george/gal/pat
.3.1.100
14
9
2
bill
george/gal/bill
.3.1.2
10
3
2
guy
george/guy
.3.2
where I have created a levels column that essentially concatenates the order1 values and separates them with a period. This almost returns the correct results, but due to the fact that I am ordering by this string (of numbers and periods), the levels value of .3.1.100 will come before .3.1.2 , which is not what the desired output should look like. I am sure there is a different method to return the correct depth order. See below for the code that generates a temp table, and the code that I used to generate the incorrect output that I have so far.
if object_id('tempdb..#t1') is not null drop table #t1
CREATE TABLE #t1 (Id int, p_Id int, order1 int, name1 varchar(150))
INSERT into #t1 VALUES
(1, null, 1, 'josh'),
(2, null, 2, 'mary'),
(3, null, 3, 'george'),
(4, 1, 1, 'joe'),
(5, 1, 2, 'jeff'),
(6, 2, 1, 'marg'),
(7, 2, 2, 'moore'),
(8, 2, 3, 'max'),
(9, 3, 1, 'gal'),
(10, 3, 2, 'guy'),
(11, 4, 1, 'tod'),
(12, 4, 2, 'ava'),
(13, 9, 1, 'ron'),
(14, 9, 2, 'bill'),
(100, 9, 100, 'pat');
select * from #t1
-- Looking to generate heiarchy results ordered by depth --
; with structure as (
-- Non-recursive term.
-- Select the records where p_Id is null
select p.Id,
p.p_Id,
p.order1,
p.name1,
cast(p.name1 as varchar(64)) as Descendants,
cast(concat('.', p.order1) as varchar(150)) as levels
from #t1 p
where p.p_Id is null
union all
-- Recursive term.
-- Treat the records from previous iteration as parents.
-- Stop when none of the current records have any further sub records.
select c.Id,
c.p_Id,
c.order1,
c.name1,
cast(concat(p.Descendants, '/', c.name1) as varchar(64)) as Descendants,
cast(concat(p.levels, '.', c.order1) as varchar(150)) as levels
from #t1 c -- c being the 'child' records
inner join structure p -- p being the 'parent' records
on c.p_Id = p.Id
)
select *
from structure
order by replace(levels, '.', '') asc
Take II. As pointed out by OP my original answer fails for more than 10 children. So what we can do (OP's suggestion) is pad the values out with zeros to a constant length. But what length? We need to take the largest number of children under a node and add this to the largest value or order, so for the example provided this is 100 + 3, and then take the length of that (3) and pad every order with zeros to 3 digits long. This means we will always be ordering as desired.
declare #PadLength int = 0;
select #PadLength = max(children)
from (
select len(convert(varchar(12),max(order1)+count(*))) children
from #t1
group by p_Id
) x;
-- Looking to generate heiarchy results ordered by depth --
with structure as (
-- Non-recursive term
-- Select the records where p_Id is null
select
p.Id [Id]
, p.p_Id [ParentId]
, p.order1 [OrderBy]
, p.name1 [Name]
, cast(p.name1 as varchar(64)) Descendants
, concat('.', right(replicate('0',#Padlength) + convert(varchar(12),p.order1), #PadLength)) Levels
from #t1 p
where p.p_Id is null
union all
-- Recursive term
-- Treat the records from previous iteration as parents.
-- Stop when none of the current records have any further sub records.
select
c.Id,
c.p_Id,
c.order1,
c.name1,
cast(concat(p.Descendants, '/', c.name1) as varchar(64)),
concat(p.levels, '.', right(replicate('0',#Padlength) + convert(varchar(12),c.order1), #PadLength))
from #t1 c -- c being the 'child' records
inner join structure p on c.p_Id = p.Id -- p being the 'parent' records
)
select *
from structure
order by replace(levels, '.', '') asc;
Note: This answer fails in the case when there are more than 10 children under a particular node. Leaving for interest.
So this issue you have run into is that you are ordering by a string not a number. So the string 100 comes before the string 2. But you need to order by a string to take care of the hierarchy, so one solution is to replace order1 with row_number() based on the order1 column while its still a number and use the row_number() to build your ordering string.
So you replace:
cast(concat(p.levels, '.', c.order1) as varchar(150)) as levels
with
cast(concat(p.levels, '.', row_number() over (order by c.Order1)) as varchar(150))
giving a full query of
with structure as (
-- Non-recursive term.
-- Select the records where p_Id is null
select p.Id,
p.p_Id,
p.order1,
p.name1,
cast(p.name1 as varchar(64)) as Descendants,
cast(concat('.', p.order1) as varchar(150)) as levels
from #t1 p
where p.p_Id is null
union all
-- Recursive term.
-- Treat the records from previous iteration as parents.
-- Stop when none of the current records have any further sub records.
select c.Id,
c.p_Id,
c.order1,
c.name1,
cast(concat(p.Descendants, '/', c.name1) as varchar(64)) as Descendants,
cast(concat(p.levels, '.', row_number() over (order by c.Order1)) as varchar(150))
from #t1 c -- c being the 'child' records
inner join structure p -- p being the 'parent' records
on c.p_Id = p.Id
)
select *
from structure
order by replace(levels, '.', '') asc;
Which returns the desired results.
Note: good question, well written.
Related
In SQL Server 2016, I have a table with the following chaining structure:
dbo.Item
OriginalItem
ItemID
NULL
7
1
2
NULL
1
5
6
3
4
NULL
8
NULL
5
9
11
2
3
EDIT NOTE: Bold numbers were added as a response to #lemon comments below
Importantly, this example is a trivialized version of the real data, and the neatly ascending entries is not something that is present in the actual data, I'm just doing that to simplify the understanding.
I've constructed a query to get what I'm calling the TerminalItemID, which in this example case is ItemID 4, 6, and 7, and populated that into a temporary table #TerminalItems, the resultset of which would look like:
#TerminalItems
TerminalItemID
4
6
7
8
11
What I need, is a final mapping table that would look something like this (using the above example -- note that it also contains for 4, 6, and 7 mapping to themselves, this is needed by the business logic):
#Mapping
ItemID
TerminalItemID
1
4
2
4
3
4
4
4
5
6
6
6
7
7
8
8
9
11
11
11
What I need help with is how to build this last #Mapping table. Any assistance in this direction is greatly appreciated!
This should do:
with MyTbl as (
select *
from (values
(NULL, 1 )
,(1, 2 )
,(2, 3 )
,(3, 4 )
,(NULL, 5 )
,(5, 6 )
,(NULL, 7 )
) T(OriginalItem, ItemID)
)
, TerminalItems as (
/* Find all leaf level items: those not appearing under OriginalItem column */
select LeafItem=ItemId, ImmediateOriginalItem=M.OriginalItem
from MyTbl M
where M.ItemId not in
(select distinct OriginalItem
from MyTbl AllParn
where OriginalItem is not null
)
), AllLevels as (
/* Use a recursive CTE to find and report all parents */
select ThisItem=LeafItem, ParentItem=ImmediateOriginalItem
from TerminalItems
union all
select ThisItem=AL.ThisItem, M.OriginalItem
from AllLevels AL
inner join
MyTbl M
on M.ItemId=AL.ParentItem
)
select ItemId=coalesce(ParentItem,ThisItem), TerminalItemId=ThisItem
from AllLevels
order by 1,2
Beware of the MAXRECURSION setting; by default SQLServer iterates through recursion 100 times; this would mean that the depth of your tree can be 100, max (the maximum number of nodes between a terminal item and its ultimate original item). This can be increased by OPTION(MAXRECURSION nnn) where nnn can be adjusted as needed. It can also be removed entirely by using 0 but this is not recommended because your data can cause infinite loops.
This is a typical gaps-and-islands problem and can also be carried out without recursion in three steps:
assign 1 at the beginning of each partition
compute a running sum over your flag value (generated at step 1)
extract the max "ItemID" on your partition (generated at step 2)
WITH cte1 AS (
SELECT *, CASE WHEN OriginalItem IS NULL THEN 1 ELSE 0 END AS changepartition
FROM Item
), cte2 AS (
SELECT *, SUM(changepartition) OVER(ORDER BY ItemID) AS parts
FROM cte1
)
SELECT ItemID, MAX(ItemID) OVER(PARTITION BY parts) AS TerminalItemID
FROM cte2
Check the demo here.
Assumption: Your terminal id items correspond to the "ItemID" value preceding a NULL "OriginalItem" value.
EDIT: "Fixing orphaned records."
The query works correctly when records are not orphaned. The only way to deal them, is to get missing records back, so that the query can work correctly on the full data.
This is carried out by an extra subquery (done at the beginning), that will apply a UNION ALL between:
the available records of the original table
the missing records
WITH fix_orphaned_records AS(
SELECT * FROM Item
UNION ALL
SELECT NULL AS OriginalItem,
i1.OriginalItem AS ItemID
FROM Item i1
LEFT JOIN Item i2 ON i1.OriginalItem = i2.ItemID
WHERE i1.OriginalItem IS NOT NULL AND i2.ItemID IS NULL
), cte AS (
...
Missing records correspond to "OriginalItem" values that are never found within the "ItemID" field. A self left join will uncover these missing records.
Check the demo here.
You can use a recursive CTE to compute the last item in the sequence. For example:
with
n (orig_id, curr_id, lvl) as (
select itemid, itemid, 1 from item
union all
select n.orig_id, i.itemid, n.lvl + 1
from n
join item i on i.originalitem = n.curr_id
)
select *
from (
select *, row_number() over(partition by orig_id order by lvl desc) as rn from n
) x
where rn = 1
Result:
orig_id curr_id lvl rn
-------- -------- ---- --
1 4 4 1
2 4 3 1
3 4 2 1
4 4 1 1
5 6 2 1
6 6 1 1
7 7 1 1
See running example at db<>fiddle.
I need to order records from a table by a column. The old system the customer was using manually selected level 1 items, then all the children of level 1 items for level 2, then so on and so forth through level 5. That is horrible IMHO, as it requires hundreds of queries and calls to the DB.
So in the new DB structure I'm trying to make it all one query to the DB if possible and have it order it correctly the first time. The customer wants it displayed to them this way so I have no choice but to figure out a way to order this way.
This is an example of the items and their level codes (1 being the single digit codes, 2 the 2 digit codes, 3 for 4 digit codes, 4 for 6 digit codes and level 5 for 8 digit codes):
It's supposed to order basically everything that starts with a 5 goes under Code 5. Everything that starts with a 51 goes under code 51. If you look at the column n_mad_id it links to the "Mother" ID of the code that is the mother of that code, so code 51's mother is code 5. Code 5101's mother is code 51. Code 5201's mother is code 52. And so on and so forth.
Then the n_nivel column is the level that the code belongs to. Each code has a level and a mother. The top level codes (i.e. 1, 2, 3, 4, 5) are all level 1 since they are only one digit.
I was hoping that there might be an easy ORDER BY way to do this. I've been playing with it for two days and can't seem to get it to obey.
The absolutely simplest way would be to cast the n_cod field to text and then order on that:
SELECT *
FROM mytable
WHERE left(n_cod::text, 1) = '5' -- optional
ORDER BY n_cod::text;
Not pretty, but functional.
You could consider changing your table definition to make n_cod of type char(8) because you do not use it as a number anyway (in the sense of performing calculations). That would make the query a lot faster.
Interesting task. As I understand that you want to get result in order like
n_id n_cod n_nivel n_mad_id
10 5 1 0
11 51 2 10
12 5101 3 11
14 510101 4 12
...
13 52 2 10
...
?
If yes then it may do the trick:
with recursive
tt(n_id, n_mad_id, n_cod, x) as (
select t.n_id, t.n_mad_id, t.n_cod, array[t.n_id]
from yourtable t where t.n_mad_id = 0
union all
select t.n_id, t.n_mad_id, t.n_cod, x || t.n_id
from tt join yourtable t on t.n_mad_id = tt.n_id)
select * from tt order by x;
Here is my original test query:
create table t(id, parent) as values
(1, null),
(3, 1),
(7, 3),
(5, 3),
(6, 5),
(2, null),
(8, 2),
(4, 2);
with recursive
tt(id, parent, x) as (
select t.id, t.parent, array[t.id] from t where t.parent is null
union all
select t.id, t.parent, x || t.id from tt join t on t.parent = tt.id)
select * from tt order by x;
and its result:
id | parent | x
----+--------+-----------
1 | (null) | {1}
3 | 1 | {1,3}
5 | 3 | {1,3,5}
6 | 5 | {1,3,5,6}
7 | 3 | {1,3,7}
2 | (null) | {2}
4 | 2 | {2,4}
8 | 2 | {2,8}
(8 rows)
Read about recursive queries.
I have a table with colors:
COLORS
idColor Name
------- ------
4 Yellow
5 Green
6 Red
And I have another table with data:
PRODUCTS
idProduct idCategory idColor
--------- ---------- -------
1 1 4
2 1 5
3 1 6
4 2 10
5 2 11
6 2 12
7 3 4
8 3 5
9 3 8
10 4 4
11 4 5
12 4 6
13 5 4
14 6 4
15 6 5
I just want return rows from Products when the idColor values from table Colors (4, 5, 6) are present in the second table and IdCategory has exactly 3 elements with the same idColor values 4, 5, 6.
For this example, The query should return:
IdCategory
----------
1
4
Try this:
SELECT idCategory
FROM PRODUCTS
GROUP BY idCategory
HAVING COUNT(*) = 3
AND COUNT(DISTINCT CASE WHEN idColor IN (4,5,6) THEN idColor END) = 3
Here is a demo for you to try.
UPDATED
If you want to dynamically filter the results depending on the values of the table `COLOR
SELECT idCategory
FROM PRODUCTS P
LEFT JOIN (SELECT idColor, COUNT(*) OVER() TotalColors
FROM COLORS) C
ON P.idColor = C.idColor
GROUP BY idCategory
HAVING COUNT(*) = MIN(C.TotalColors)
AND COUNT(DISTINCT C.idColor) = MIN(C.TotalColors)
Here is a fiddle with this example.
You can use aggregates to make sure it has all 3 colors, and also to make sure it DOESN'T have any other colors. Something like this:
SELECT *
FROM
(
SELECT idCategory
, SUM(CASE WHEN idColor IN (4, 5, 6) THEN 1 ELSE 0 END) AS GoodColors
, SUM(CASE WHEN idColor NOT IN (4, 5, 6) THEN 1 ELSE 0 END) AS BadColors
FROM Products
GROUP BY idCategory
) t0
WHERE GoodColors = 3 AND BadColors = 0
Note, if the 4, 5, 6 is found more than once per idCategory then a different technique must be employed. But from your example, it doesn't appear that way.
I am guessing that you would like to perform this task based on data in a table, rather than hardcoding the values 4, 5, and 6 (like in some of the answers given). To that end, in my solution I created a dbo.ColorSets table that you can fill with as many different sets of colors as you want, then run the query and see all the product Categories that match those color Sets. The reason I didn't just use your dbo.Color table is that it appeared to be the lookup table, complete with color names, so it didn't seem like the right one to be picking out a particular set of colors rather than the entire list possible.
I used a technique that will maintain good performance even on huge amounts of data, as compared to other query methods that use aggregates exclusively. No matter what method one uses, this task will pretty much always require a scan of the entire Products table because you can't compare all the rows without, well, comparing all the rows. But the JOIN is on indexable columns and is only for the candidates that have a very good chance of being proper matches, so the amount of work required is greatly reduced.
Here's what the ColorSets table looks like:
CREATE TABLE dbo.ColorSets (
idSet int NOT NULL,
idColor int NOT NULL,
CONSTRAINT PK_ColorSet PRIMARY KEY CLUSTERED (idSet, idColor)
);
INSERT dbo.ColorSets
VALUES
(1, 4),
(1, 5),
(1, 6), -- your color set: yellow, green, and red
(2, 4),
(2, 5),
(2, 8) -- an additional color set: yellow, green, and purple
;
And the query (see this working in a SqlFiddle):
WITH Sets AS (
SELECT
idSet,
Grp = Checksum_Agg(idColor)
FROM
dbo.ColorSets
GROUP BY
idSet
), Categories AS (
SELECT
idCategory,
Grp = Checksum_Agg(idColor)
FROM
dbo.Products
GROUP BY
idCategory
)
SELECT
S.idSet,
C.idCategory
FROM
Sets S
INNER JOIN Categories C
ON S.Grp = C.Grp
WHERE
NOT EXISTS (
SELECT *
FROM
(
SELECT *
FROM dbo.ColorSets CS
WHERE CS.idSet = S.idSet
) CS
FULL JOIN (
SELECT *
FROM dbo.Products P
WHERE P.idCategory = C.idCategory
) P
ON CS.idColor = P.idColor
WHERE
CS.idColor IS NULL
OR P.idColor IS NULL
)
;
Result:
idSet idCategory
1 1
2 3
1 4
If I understand your question, this should do it
select distinct idCategory
from Products
where idColors in (4,5,6)
I have a table with part of data like below . I have done order by on edition_id .
Now there is further requirement of ordering laungauge_id which depends on value of edition_id.
Edition_id refers to city from which a newspaper is published.
Language_id refers to different languages in which newspaper is
published.
So suppose edition_id = 5 it means New Delhi.
For New Delhi language_id are 13(English ), 5 (Hindi) ,1(Telugu ),4(Urdu).
What i want is to display for New Delhi , is display all English articles first , followed by hindi , followed by Telugu followed by Urdu.
If edition_id=1 then order of language_id should be 13,1,2.
Similarly ,
If edition_id=5 then order of language_id should be 13,5,1,4
Right now what I have is
Edition_id | Language_id
1 1
1 2
1 13
1 1
1 13
1 2
5 4
5 1
5 1
5 4
5 13
5 5
5 13
What is required
Edition_id | Language_id
1 13
1 13
1 1
1 1
1 2
1 2
5 13
5 13
5 5
5 1
5 1
5 4
5 4
How to do this ? Please help.
Is something like this possibe
Select * from <table>
order by edition_id ,
case when edition=6 then <order specified for language_id ie 13,5,1,4>
I would create a supplementary ranking table. I would then JOIN to provide your sort order. Eg:
EDITION_SORT_ORDER
EDITION_ID LANGUAGE_ID RANK
---------- ----------- ----
1 13 1
1 1 2
1 2 3
5 13 1
5 5 2
5 1 3
5 4 4
Using this table in a query might look like this:
SELECT E.EDITION_ID, E.LANGUAGE_ID
FROM <TABLE> E LEFT OUTER JOIN EDITION_SORT_ORDER S ON
E.EDITION_ID = S.EDITION_ID AND
E.LANGUAGE_ID = S.LANGUAGE_ID
ORDER BY S.RANK
This way you can add other rules in future, and it isn't a huge mess of CASE logic.
Alternatively, if you want to avoid a JOIN, you could create a stored function which did a similar lookup and returned a rank (based on passed parameters of EDITION_ID and LANGUAGE_ID).
If you must use CASE, then I'd confine it to a function so you can re-use the logic elsewhere.
If there is no mathematical logic behind it, I would insert another column that can be used for proper sorting.
If you cannot do this, you can simply type out the rules for the relation like this:
Order By Edition_Id,
case Edition_id
when 1 then
case Language_id
when 13 then 1
when 1 then 2
when 2 then 3
end
when 5 then
case Language_id
when 13 then 1
when 5 then 2
when 1 then 3
when 4 then 4
end
end
without a fixed order colum you could things like that, but the logic is not comprehensible.
Assuming first criteria is length of Language_id,
Second is Edition_id= Language_id,
rest is order of Language_id it could or work this way:
Declare #t table(Edition_id int, Language_id int)
insert into #t values
(1, 1),
(1, 2),
(1, 13),
(1, 1),
(1, 13),
(1, 2),
(5, 4),
(5, 1),
(5, 1),
(5, 4),
(5, 13),
(5, 5),
(5, 13);
Select * from #t
order by Edition_id,Case when len (Cast(Language_ID as Varchar(10)))=1 then '1' else '0' end
+case when Edition_id=Language_id then '0' else '1' end
,Language_ID
You've probably considered this but if your desired ordering is always based of the actual alphabetical name of the language then there would usually be a table with the language description that you could join with and then sort by. I base this on your quote below.
...English articles first , followed by hindi , followed by Telugu
followed by Urdu.
SELECT E.EDITION_ID, E.LANGUAGE_ID, LN.LANGUAGE_NAME
FROM <TABLE> E LEFT OUTER JOIN <LANGUAGE_NAMES> LN ON
E.LANGUAGE_ID = LN.LANGUAGE_ID
ORDER BY 1, 3
for a simple data structure such as so:
ID parentID Text Price
1 Root
2 1 Flowers
3 1 Electro
4 2 Rose 10
5 2 Violet 5
6 4 Red Rose 12
7 3 Television 100
8 3 Radio 70
9 8 Webradio 90
For reference, the hierarchy tree looks like this:
ID Text Price
1 Root
|2 Flowers
|-4 Rose 10
| |-6 Red Rose 12
|-5 Violet 5
|3 Electro
|-7 Television 100
|-8 Radio 70
|-9 Webradio 90
I'd like to count the number of children per level. So I would get a new column "NoOfChildren" like so:
ID parentID Text Price NoOfChildren
1 Root 8
2 1 Flowers 3
3 1 Electro 3
4 2 Rose 10 1
5 2 Violet 5 0
6 4 Red Rose 12 0
7 3 Television 100 0
8 3 Radio 70 1
9 8 Webradio 90 0
I read a few things about hierarchical data, but I somehow get stuck on the multiple inner joins on the parentIDs. Maybe someone could help me out here.
Using a CTE would get you what you want.
Recursively go through all children, remembering the root.
COUNT the items for each root.
JOIN these again with your original table to produce the results.
Test Data
DECLARE #Data TABLE (
ID INTEGER PRIMARY KEY
, ParentID INTEGER
, Text VARCHAR(32)
, Price INTEGER
)
INSERT INTO #Data
SELECT 1, Null, 'Root', NULL
UNION ALL SELECT 2, 1, 'Flowers', NULL
UNION ALL SELECT 3, 1, 'Electro', NULL
UNION ALL SELECT 4, 2, 'Rose', 10
UNION ALL SELECT 5, 2, 'Violet', 5
UNION ALL SELECT 6, 4, 'Red Rose', 12
UNION ALL SELECT 7, 3, 'Television', 100
UNION ALL SELECT 8, 3, 'Radio', 70
UNION ALL SELECT 9, 8, 'Webradio', 90
SQL Statement
;WITH ChildrenCTE AS (
SELECT RootID = ID, ID
FROM #Data
UNION ALL
SELECT cte.RootID, d.ID
FROM ChildrenCTE cte
INNER JOIN #Data d ON d.ParentID = cte.ID
)
SELECT d.ID, d.ParentID, d.Text, d.Price, cnt.Children
FROM #Data d
INNER JOIN (
SELECT ID = RootID, Children = COUNT(*) - 1
FROM ChildrenCTE
GROUP BY RootID
) cnt ON cnt.ID = d.ID
Consider using a modified preorder tree traversal way of storing the hierarchical data. See http://www.sitepoint.com/hierarchical-data-database/
Determining number of children for any node then becomes a simple:
SELECT (right-left-1) / 2 AS num_children FROM ...