Hi all. Take this example from src/test/regress/sql/with.sql: WITH RECURSIVE subdepartment(level, id, parent_department, name) AS ( -- non recursive term SELECT 1, * FROM department WHERE name = 'A'
UNION ALL -- recursive term SELECT sd.level + 1, d.* FROM department AS d, subdepartment AS sd WHERE d.parent_department = sd.id ) SELECT * FROM subdepartment ORDER BY name; level | id | parent_department | name -------+----+-------------------+------ 1 | 1 | 0 | A 2 | 2 | 1 | B 3 | 3 | 2 | C 3 | 4 | 2 | D 4 | 6 | 4 | F (5 rows) If I omit "ORDER BY", is the output *guaranteed* (according to some standard) to be ordered in "hierarchy"-order, meaning each parent-department is always output before its respective child, or do I have to calculate a "level" column (like in the example above) and specify "ORDER BY LEVEL" to be 100%? I'm using WITH RECURSIVE as sub-queries to build up arrays of parents in each output-row and would like as little overhead as possible and hence avoid unnecessary sorting. -- Andreas Joseph Krogh <andr...@officenet.no> Senior Software Developer / CTO ------------------------+---------------------------------------------+ OfficeNet AS | The most difficult thing in the world is to | Rosenholmveien 25 | know how to do a thing and to watch | 1414 TrollÄsen | somebody else doing it wrong, without | NORWAY | comment. | | | Tlf: +47 24 15 38 90 | | Fax: +47 24 15 38 91 | | Mobile: +47 909 56 963 | | ------------------------+---------------------------------------------+ -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql