https://gist.github.com/wishdev/635f7a839877d79a6781
Sorry for the 3rd party site - just easier to get the layout correct.
A CTE and dense_rank is all it takes. I am always amazed at what one can
now pack into such small amounts of code.
On Wed, Jul 23, 2014 at 4:00 PM, Jim Garrison wrote:
I wouldn't do this with recursion; plain old iteration is your friend
(yes, WITH RECURSIVE is actually iterative, not recursive...)
The algorithm goes like this:
1. Extend your graph relation to be symmetric and transitive.
2. Assign a integer group id to each node.
3. Repeatedly join the node li
I have a collection of relationship rows of the form
Table: graph
key1 varchar
key2 varchar
A row of the form ('a','b') indicates that 'a' and 'b' are related.
The table contains many relationships between keys, forming several
disjoint sets. All relationships are bi-directional, and both
