SQL Recursive CTE unexpectedly returns alternating sets - sql

Question

I am trying to get the use recursive CTE to repeat the same pattern over and over, resetting when "Scenario" increases in value. RowNumber repeats 1-21 (as desired), but whenever "Scenario" is an even number, there are too few items in the "Vals" column to feed into "Value". I can't figure out which part of the code is causing me to be 1 short for only even Scenarios.
Below are the results of the code I'm using at the bottom.
Scenario RowNumber Value Vals
1 1 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,C
1 2 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,C
1 3 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,C
1 4 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,C
1 5 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,C
1 6 A A,A,A,A,A,A,A,A,A,A,A,A,A,B,C
1 7 A A,A,A,A,A,A,A,A,A,A,A,A,B,C
1 8 A A,A,A,A,A,A,A,A,A,A,A,B,C
1 9 A A,A,A,A,A,A,A,A,A,A,B,C
1 10 A A,A,A,A,A,A,A,A,A,B,C
1 11 A A,A,A,A,A,A,A,A,B,C
1 12 A A,A,A,A,A,A,A,B,C
1 13 A A,A,A,A,A,A,B,C
1 14 A A,A,A,A,A,B,C
1 15 A A,A,A,A,B,C
1 16 A A,A,A,B,C
1 17 A A,A,B,C
1 18 A A,B,C
1 19 A B,C
1 20 B C
1 21 C
2 1 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,B,C
2 2 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,B,C
2 3 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,B,C
2 4 A A,A,A,A,A,A,A,A,A,A,A,A,A,B,B,C
2 5 A A,A,A,A,A,A,A,A,A,A,A,A,B,B,C
2 6 A A,A,A,A,A,A,A,A,A,A,A,B,B,C
2 7 A A,A,A,A,A,A,A,A,A,A,B,B,C
2 8 A A,A,A,A,A,A,A,A,A,B,B,C
2 9 A A,A,A,A,A,A,A,A,B,B,C
2 10 A A,A,A,A,A,A,A,B,B,C
2 11 A A,A,A,A,A,A,B,B,C
2 12 A A,A,A,A,A,B,B,C
2 13 A A,A,A,A,B,B,C
2 14 A A,A,A,B,B,C
2 15 A A,A,B,B,C
2 16 A A,B,B,C
2 17 A B,B,C
2 18 B B,C
2 19 B C
2 20 C
2 21 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,B,C
3 1 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,C,C
3 2 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,C,C
3 3 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,C,C
3 4 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,C,C
3 5 A A,A,A,A,A,A,A,A,A,A,A,A,A,B,C,C
3 6 A A,A,A,A,A,A,A,A,A,A,A,A,B,C,C
3 7 A A,A,A,A,A,A,A,A,A,A,A,B,C,C
3 8 A A,A,A,A,A,A,A,A,A,A,B,C,C
3 9 A A,A,A,A,A,A,A,A,A,B,C,C
3 10 A A,A,A,A,A,A,A,A,B,C,C
3 11 A A,A,A,A,A,A,A,B,C,C
3 12 A A,A,A,A,A,A,B,C,C
3 13 A A,A,A,A,A,B,C,C
3 14 A A,A,A,A,B,C,C
3 15 A A,A,A,B,C,C
3 16 A A,A,B,C,C
3 17 A A,B,C,C
3 18 A B,C,C
3 19 B C,C
3 20 C C
3 21 C
4 1 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,B,B,C
4 2 A A,A,A,A,A,A,A,A,A,A,A,A,A,A,B,B,B,C
4 3 A A,A,A,A,A,A,A,A,A,A,A,A,A,B,B,B,C
4 4 A A,A,A,A,A,A,A,A,A,A,A,A,B,B,B,C
4 5 A A,A,A,A,A,A,A,A,A,A,A,B,B,B,C
4 6 A A,A,A,A,A,A,A,A,A,A,B,B,B,C
4 7 A A,A,A,A,A,A,A,A,A,B,B,B,C
4 8 A A,A,A,A,A,A,A,A,B,B,B,C
4 9 A A,A,A,A,A,A,A,B,B,B,C
4 10 A A,A,A,A,A,A,B,B,B,C
4 11 A A,A,A,A,A,B,B,B,C
4 12 A A,A,A,A,B,B,B,C
4 13 A A,A,A,B,B,B,C
4 14 A A,A,B,B,B,C
4 15 A A,B,B,B,C
4 16 A B,B,B,C
4 17 B B,B,C
4 18 B B,C
4 19 B C
4 20 C
This is the code I used to generate the above sample. Where am I going wrong?
CREATE TABLE #temp3
(
Scenario INT
,Vals VARCHAR(64)
,LEN INT
)
;
WITH vals AS
(
SELECT
v.*
FROM
(VALUES ('A'), ('B'), ('C')) v(x)
),
CTE AS
(
SELECT CAST('A' AS VARCHAR(MAX)) AS STR, 0 AS LEN
UNION ALL
SELECT (CTE.STR + ',' + vals.x), CTE.LEN + 1
FROM
CTE
JOIN vals
ON vals.x >= RIGHT(CTE.STR, 1)
WHERE CTE.LEN < 19
)
INSERT INTO #temp3
SELECT
ROW_NUMBER() OVER(ORDER BY STR + ',C') AS Scenario
,STR + ',C' AS Vals
,LEN
FROM
CTE
WHERE
STR + 'C' LIKE '%B%'
AND LEN = 19
;
-- Split strings created above into individual characters
WITH cte(Scenario, Value, Vals) AS
(
SELECT
Scenario
,CAST(LEFT(Vals, CHARINDEX(',',Vals+',')-1) AS VARCHAR(10)) AS Value
,STUFF(Vals, 1, CHARINDEX(',',Vals+','), '') AS Vals
FROM #temp3
UNION ALL
SELECT
Scenario
,CAST(LEFT(Vals, CHARINDEX(',',Vals+',')-1) AS VARCHAR(10))
,STUFF(Vals, 1, CHARINDEX(',',Vals+','), '')
FROM cte
WHERE Vals > ''
)
SELECT
Scenario
,ROW_NUMBER() OVER (PARTITION BY Scenario ORDER BY Scenario) RowNumber
,Value
,Vals
FROM cte t

Answer 1

I'm not exactly sure what the problem you are describing is, but the ROW_NUMBER() should use an ORDER BY clause that completely orders the rows in each partition.
When you use "PARTITION BY Scenario ORDER BY Scenario" the order in which the ROW_NUMBER() values are assigned is undefined. Try something like
WITH cte(Scenario, depth, Value, Vals) AS
(
SELECT
Scenario, 0 depth
,CAST(LEFT(Vals, CHARINDEX(',',Vals+',')-1) AS VARCHAR(10)) AS Value
,STUFF(Vals, 1, CHARINDEX(',',Vals+','), '') AS Vals
FROM #temp3
UNION ALL
SELECT
Scenario, depth+1
,CAST(LEFT(Vals, CHARINDEX(',',Vals+',')-1) AS VARCHAR(10))
,STUFF(Vals, 1, CHARINDEX(',',Vals+','), '')
FROM cte
WHERE Vals > ''
)
SELECT
Scenario
,depth
,ROW_NUMBER() OVER (PARTITION BY Scenario ORDER BY depth ) RowNumber
,Value
,Vals
FROM cte t