Need query to select direct and indirect customerID aliases - sql

Question

I need a query that will return all related alias id's from either column. Shown here are some alias customer ids, among thousands of other rows. If the input parameter to a query is id=7, I need a query that would return 5 rows (1,5,7,10,22). That is because they are all aliases of one-another. For example, 22 and 10 are indirect aliases of 7.
CustomerAlias
--------------------------
AliasCuID AliasCuID2
--------------------------
1 5
1 7
5 7
10 5
22 1
Here is an excerpt from the customer table.
Customer
----------------------------------
CuID CuFirstName CuLastName
----------------------------------
1 Mike Jones
2 Fred Smith
3 Jack Jackson
4 Emily Simpson
5 Mike Jones
6 Beth Smith
7 Mike jones
8 Jason Robard
9 Emilie Jiklonmie
10 Michael jones
11 Mark Lansby
12 Scotty Slash
13 Emilie Jiklonmy
22 mike jones
I've been able to come close, but I cannot seem to select the indirectly related aliases correctly. Given this query:
SELECT DISTINCT Customer.CuID, Customer.CuFirstName, Customer.CuLastName
FROM Customer WHERE
(Customer.CuID = 7) OR (Customer.CuID IN
(SELECT AliasCuID2
FROM CustomerAlias AS CustomerAlias_2
WHERE (AliasCuID = 7))) OR (Customer.CuID IN
(SELECT AliasCuID
FROM CustomerAlias AS CustomerAlias_1
WHERE (AliasCuID2 = 7)))
Returns 3 out of 5 of the desired ids of course. This lacks the indirectly related aliased id of 10 and 22 in the result rows.
1 Mike Jones
5 Mike Jones
7 Mike jones
* Based on suggestions below, I am trying a CTE hierarchical query.
I have this now after following some suggestions. It works for some, as long as the records in the table reference enough immediate ids. But, if the query uses id=10, then it still comes up short, just by the nature of the data.
DECLARE #id INT
SET #id = 10;
DECLARE #tmp TABLE ( a1 INT, a2 INT, Lev INT );
WITH Results (AliasCuID, AliasCuID2, [Level]) AS (
SELECT AliasCuID,
AliasCuID2,
0 as [Level]
FROM CustomerAlias
WHERE AliasCuID = #id OR AliasCuID2 = #id
UNION ALL
-- Recursive step
SELECT a.AliasCuID,
a.AliasCuID2,
r.[Level] + 1 AS [Level]
FROM CustomerAlias a
INNER JOIN Results r ON a.AliasCuID = r.AliasCuID2 )
INSERT INTO #tmp
SELECT * FROM Results;
WITH Results3 (AliasCuID, AliasCuID2, [Level]) AS (
SELECT AliasCuID,
AliasCuID2,
0 as [Level]
FROM CustomerAlias
WHERE AliasCuID = #id OR AliasCuID2 = #id
UNION ALL
-- Recursive step
SELECT a.AliasCuID,
a.AliasCuID2,
r.[Level] + 1 AS [Level]
FROM CustomerAlias a
INNER JOIN Results3 r ON a.AliasCuID2 = r.AliasCuID )
INSERT INTO #tmp
SELECT * FROM Results3;
SELECT DISTINCT a1 AS id FROM #tmp
UNION ALL
SELECT DISTINCT a2 AS id FROM #tmp
ORDER BY id
Note that this is a simplified the query to just give a list of related ids.
---
id
---
5
5
7
10
But, it is still unable to pull in ids 1 and 22.

Answer 1

This is not an easy problem to solve unless you have some idea of the depth of your search (https://stackoverflow.com/a/7569520/1803682) - which it looks like you do not - and take a brute force approach to it.
Assuming you do not know the depth you will need to write a stored proc. I followed this approach for a nearly identical problem: https://dba.stackexchange.com/questions/7147/find-highest-level-of-a-hierarchical-field-with-vs-without-ctes/7161#7161
UPDATE
If you don't care about the chain of how the alias's were created - I would run a script recursively to make them all refer to a single (master?) record. Then you can easily do the search and it will be quick - not a solution if you care about how the alias's get traversed though.

Answer 2

I created a SQL Fiddle for SQL Server 2012. Please let me know if you can or cannot access it.
My thought here was that you'd want to just keep checking the left and right branches recursively, separately. This logic probably falls apart if the relationships bounce between left and right. You could set up a third CTE to reference the first two, but joining on left to right and right to left, but ain't nobody got time for that.
The code is below as well.
CREATE TABLE CustomerAlias
(
AliasCuID INT,
AliasCuID2 INT
)
GO
INSERT INTO CustomerAlias
SELECT 1,5
UNION SELECT 1, 7
UNION SELECT 5, 7
UNION SELECT 10, 5
UNION SELECT 22, 1
GO
DECLARE #Value INT
SET #Value = 7
; WITH LeftAlias AS
(
SELECT AliasCuID
, AliasCuID2
FROM CustomerAlias
WHERE AliasCuID2 = #Value
UNION ALL
SELECT a.AliasCuID
, a.AliasCuID2
FROM CustomerAlias a
JOIN LeftAlias b
ON a.AliasCuID = b.AliasCuID2
)
, RightAlias AS
(
SELECT AliasCuID
, AliasCuID2
FROM CustomerAlias
WHERE AliasCuID = #Value
UNION ALL
SELECT a.AliasCuID
, a.AliasCuID2
FROM CustomerAlias a
JOIN LeftAlias b
ON a.AliasCuID2 = b.AliasCuID
)
SELECT DISTINCT A
FROM
(
SELECT A = AliasCuID
FROM LeftAlias
UNION ALL
SELECT A = AliasCuID2
FROM LeftAlias
UNION ALL
SELECT A = AliasCuID
FROM RightAlias
UNION ALL
SELECT A = AliasCuID2
FROM RightAlias
) s
ORDER BY A