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SQL Recursion woes

Matthew Snow
Ranch Hand

Joined: May 02, 2007
Posts: 82
I have a table that stores tree structures, the tree name and nodes in the tree with their respective parent node. Here's an example:

Tree Name | Node Name | Parent Node Name
Business | Group A |
Business | Group Aa | Group A
Design | Group A |
Design | Group Aa | Group A

As you can see, the Node Names are reusable between the trees. I'm trying to recurse through this table to display the structure of each tree. Unfortunately, since the Node Names are reused between the trees, using a Connect By Prior Node Name = Parent Node Name is causing it to skip between the trees as it recurses. What I need to do as I connect to a lower recursion level is to make sure that the Tree Name has not changed so as to make sure it's still recursing the same tree. Here is the SQL that I have, and SQL Developer takes it as a valid SQL:

select TreeName, NodeName
from TreeTable
start with TreeName in (select distinct TreeName from TreeTable)
connect by prior TreeName = TreeName
connect by prior NodeName = ParentNodeName

However this isn't solving the problem. It's still skipping between trees. From what I can tell, even though our Oracle 10g says this is a valid SQL, it's ignoring all but the last Connect By Prior clause. Any help would be appreciated.

P.S. using Start With TreeName = 'Business' does not help as this constraint only applies at the start of the recursion, as the command name implies. Once it goes down to Level 2 and below it starts skipping between the trees.

When you break the big rules, you get a lot of little rules.
Matthew Snow
Ranch Hand

Joined: May 02, 2007
Posts: 82
Using a AND PRIOR element = element will solve the problem.
I agree. Here's the link:
subject: SQL Recursion woes
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