वैसे मैं ओरेकल के लिए कुछ नहीं कह सकता, लेकिन आप इसे एसक्यूएल सर्वर में रिकर्सिव सीटीई के साथ प्रबंधित कर सकते हैं। यहाँ मेरा नमूना समाधान है, यह वही करता है जो आपने यह मानने के लिए कहा था कि आपके पास एक टेबल विच मैप्स है जो एक टेबल से कई-से-कई से संबंधित है
DECLARE @testData table (EntityID int, EntityName varchar(1))
DECLARE @EntityRelations table (EntityID1 int, EntityID2 int)
INSERT INTO @testData
SELECT 1, 'A'
UNION
SELECT 2, 'B'
UNION
SELECT 3, 'C'
UNION
SELECT 4, 'D'
UNION
SELECT 5, 'E'
UNION
SELECT 6, 'F'
UNION
SELECT 7, 'G'
UNION
SELECT 8, 'Y'
UNION
SELECT 9, 'Z'
INSERT INTO @EntityRelations
SELECT 1, 2
UNION
SELECT 9, 2
UNION
SELECT 8, 2
UNION
SELECT 2, 3
UNION
SELECT 2, 4
UNION
SELECT 4, 5
UNION
SELECT 6, 7;
WITH Affiliations (EntityID, Entity1Name, Entity2Name) AS
(
SELECT r.EntityID1
,e.EntityName as Entity1Name
,e2.EntityName as Entity2Name
FROM @EntityRelations r
JOIN @testData e ON e.EntityID = r.EntityID1
JOIN @testData e2 ON e2.EntityID = r.EntityID2
UNION ALL
SELECT r.EntityID1
,e.EntityName as Entity1Name
,e2.EntityName as Entity2Name
FROM @EntityRelations r
JOIN @testData e ON e.EntityID = r.EntityID1
JOIN @testData e2 ON e2.EntityID = r.EntityID2
JOIN Affiliations a ON a.EntityID = r.EntityID2
)
,AffiliationsReverse (EntityID, Entity1Name, Entity2Name) AS
(
SELECT r.EntityID2
,e.EntityName as Entity1Name
,e2.EntityName as Entity2Name
FROM @EntityRelations r
JOIN @testData e ON e.EntityID = r.EntityID1
JOIN @testData e2 ON e2.EntityID = r.EntityID2
UNION ALL
SELECT r.EntityID2
,e.EntityName as Entity1Name
,e2.EntityName as Entity2Name
FROM @EntityRelations r
JOIN @testData e ON e.EntityID = r.EntityID1
JOIN @testData e2 ON e2.EntityID = r.EntityID2
JOIN AffiliationsReverse a ON a.EntityID = r.EntityID1
)
SELECT DISTINCT EntityName
FROM
(
SELECT a.Entity1Name AS EntityName
FROM Affiliations a
JOIN AffiliationsReverse ar ON ar.EntityID = a.EntityID
UNION
SELECT a.Entity2Name AS EntityName
FROM Affiliations a
JOIN AffiliationsReverse ar ON ar.EntityID = a.EntityID
UNION
SELECT ar.Entity1Name AS EntityName
FROM Affiliations a
JOIN AffiliationsReverse ar ON ar.EntityID = a.EntityID
UNION
SELECT ar.Entity2Name AS EntityName
FROM Affiliations a
JOIN AffiliationsReverse ar ON ar.EntityID = a.EntityID
) s