Ordering the siblings v16
You can order the result set so the siblings appear in ascending or descending order by selected column values using the
ORDER SIBLINGS BY clause. This is a special case of the
ORDER BY clause that you can use only with hierarchical queries.
You can further modify the previous query by adding
ORDER SIBLINGS BY ename
The output from the prior query is now modified so the siblings appear in ascending order by name. Siblings
JONES are now alphabetically arranged under
WARD are alphabetically arranged under
BLAKE, and so on.
This final example adds the
WHERE clause and starts with three root nodes. After the node tree is constructed, the
WHERE clause filters out rows in the tree to form the result set.
The output from the query shows three root nodes (level one):
JONES. In addition, rows that don't satisfy the
WHERE clause were eliminated from the output.