2024年1月29日 · Recursive common table expressions provide the ability to do hierarchical or recursive queries of trees and graphs, a capability that is not otherwise available in the SQL language. All common table expressions (ordinary and recursive) are created by prepending a WITH clause in front of a SELECT, INSERT, DELETE, or UPDATE statement.

You can use a recursive CTE to find the paths in an undirected cyclic graph. But you must design the SQL explicitly to accommodate the fact that the edges are undirected and you must include an explicit predicate to prevent cycles.

2025年3月21日 · In GoogleSQL for BigQuery, a WITH clause contains one or more common table expressions (CTEs) with temporary tables that you can reference in a query expression. CTEs can be non-recursive,...

2019年9月24日 · The table @Graph contains relationships (edges) between the nodes. I want a list of the nodes that are related. Using the desired result I can group all the nodes that are related by the 2nd value in the result.

To illustrate what the Recursive CTE is capable of, we'll make some brief forays into graph traversal and sorting algorithms and how these can be implemented in SQL to make queries about the structure of complex foreign key relationships.

2017年4月24日 · To clarify GetActivities ('a'). This function should find the 'Start' activity of 'a' and proceed to find any 'Transfer' activities on 'a'. At that the point the function can then recurse with 'b' and consequently 'c' with the sample data. The query should return all …

2023年5月19日 · For cyclic graphs, if you wanted to visit each node only once, then you can workaround the redundancy issue by keeping track of nodes that were already visited, on each iteration of the recursion. One way to do that is by building a string of already visited nodes with a separator and doing a wildcard contains search, like such:

2021年3月30日 · I'm using a recursive Common Table Expression in SQLite to traverse a graph. How can I avoid cycles in the traversal while also limiting the depth of the search? For example, here's a very basic graph, represented as an edge list, with 3 nodes (in my case, the graph is directed but most edges are linked in both directions, similar to what's ...

2024年5月9日 · Users often turn to specialized solutions such as graph databases—Cypher for Neo4J and AQL for ArangoDB, for instance—to handle complex data structures. Couchbase sets itself apart with SQL for JSON, offering a unique approach to Recursive CTEs that also extend its multi model support.

2024年5月12日 · Recursive CTEs are a powerful feature in PostgreSQL that allows for the easy implementation of graph traversal algorithms. By using a CTE in a recursive manner, we can traverse a graph, level by level, and perform various operations on the nodes and edges.