You are right, finding the shortest path through the brute force method (depth-first graph traversal while avoiding circuits) is easy to express with a CTE but implementing Dijkstra's algorithm is far less trivial. The main obstacle is that the current resultset of a CTE (the set of rows already computed) is "append only": one can augment it through the recursive member of the CTE but there is no way to delete or update its rows. Personally, I'm (almost) sure that it is possible to design a CTE that simulates 'delete' and 'update' operations, for example by adding a 'version' attribute to its rows, and by selecting their last version, just like in a historical database. But I guess that the expression would be particularly complex, not to mention poorer performance. Sometimes, a carefully crafted procedural solution can be clearer and faster that its equivalent declarative expression ! As to your observation "You don't even need SQL to do it at all.", you also are right. Anyway, it's even possible to solve the shortest path problem through a Turing machine ;).