Which will return Amanda, Ralph, and Jeanne. If you want to get ancestors to a given node say 7-8 Ralph. What SQL query you will write?

by

SELECT * FROM employee WHERE left_val < 7 and right_val > 8 WHERE ORDER BY left_val ASC;

To retrieve ancestors of a given node in a hierarchical structure stored in a database using SQL, you typically use recursive queries, which are supported by some relational database management systems (RDBMS) like PostgreSQL, SQL Server, and Oracle. Assuming you’re using a database system that supports recursive queries, here’s an example SQL query:

sql
WITH RECURSIVE Ancestors AS (
SELECT id, parent_id, name
FROM YourTable
WHERE id = 7 -- Assuming 7 is the ID of the node you want to start fromUNION ALL

SELECT t.id, t.parent_id, t.name
FROM YourTable t
INNER JOIN Ancestors a ON t.id = a.parent_id
)
SELECT name
FROM Ancestors;

Replace YourTable with the actual name of your table. This query will return the ancestors of the node with the ID 7, starting from itself and recursively going up the hierarchy until reaching the root node.

This assumes a table structure where each row represents a node with columns id, parent_id, and name, where id is the unique identifier of the node, parent_id is the ID of its parent node, and name is the name of the node. Adjust the column names according to your actual schema.