2008-10-04 23:56:55 +02:00
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--
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-- Tests for common table expressions (WITH query, ... SELECT ...)
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--
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-- Basic WITH
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WITH q1(x,y) AS (SELECT 1,2)
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SELECT * FROM q1, q1 AS q2;
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-- Multiple uses are evaluated only once
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SELECT count(*) FROM (
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WITH q1(x) AS (SELECT random() FROM generate_series(1, 5))
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SELECT * FROM q1
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UNION
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SELECT * FROM q1
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) ss;
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-- WITH RECURSIVE
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-- sum of 1..100
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WITH RECURSIVE t(n) AS (
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VALUES (1)
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UNION ALL
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SELECT n+1 FROM t WHERE n < 100
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)
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SELECT sum(n) FROM t;
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WITH RECURSIVE t(n) AS (
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SELECT (VALUES(1))
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UNION ALL
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SELECT n+1 FROM t WHERE n < 5
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)
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SELECT * FROM t;
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2008-10-07 21:27:04 +02:00
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-- This is an infinite loop with UNION ALL, but not with UNION
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WITH RECURSIVE t(n) AS (
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SELECT 1
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UNION
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SELECT 10-n FROM t)
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SELECT * FROM t;
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2008-10-04 23:56:55 +02:00
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-- This'd be an infinite loop, but outside query reads only as much as needed
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WITH RECURSIVE t(n) AS (
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VALUES (1)
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UNION ALL
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SELECT n+1 FROM t)
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SELECT * FROM t LIMIT 10;
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2008-10-07 21:27:04 +02:00
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-- UNION case should have same property
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WITH RECURSIVE t(n) AS (
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SELECT 1
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UNION
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SELECT n+1 FROM t)
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SELECT * FROM t LIMIT 10;
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2008-10-06 00:50:55 +02:00
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-- Test behavior with an unknown-type literal in the WITH
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WITH q AS (SELECT 'foo' AS x)
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SELECT x, x IS OF (unknown) as is_unknown FROM q;
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WITH RECURSIVE t(n) AS (
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SELECT 'foo'
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UNION ALL
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SELECT n || ' bar' FROM t WHERE length(n) < 20
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)
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SELECT n, n IS OF (text) as is_text FROM t;
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2008-10-04 23:56:55 +02:00
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--
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-- Some examples with a tree
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--
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-- department structure represented here is as follows:
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--
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-- ROOT-+->A-+->B-+->C
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-- | |
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-- | +->D-+->F
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-- +->E-+->G
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CREATE TEMP TABLE department (
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id INTEGER PRIMARY KEY, -- department ID
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parent_department INTEGER REFERENCES department, -- upper department ID
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name TEXT -- department name
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);
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INSERT INTO department VALUES (0, NULL, 'ROOT');
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INSERT INTO department VALUES (1, 0, 'A');
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INSERT INTO department VALUES (2, 1, 'B');
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INSERT INTO department VALUES (3, 2, 'C');
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INSERT INTO department VALUES (4, 2, 'D');
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INSERT INTO department VALUES (5, 0, 'E');
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INSERT INTO department VALUES (6, 4, 'F');
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INSERT INTO department VALUES (7, 5, 'G');
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-- extract all departments under 'A'. Result should be A, B, C, D and F
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WITH RECURSIVE subdepartment AS
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(
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-- non recursive term
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2008-10-06 00:20:17 +02:00
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SELECT name as root_name, * FROM department WHERE name = 'A'
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2008-10-04 23:56:55 +02:00
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UNION ALL
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-- recursive term
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2008-10-06 00:20:17 +02:00
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SELECT sd.root_name, d.* FROM department AS d, subdepartment AS sd
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2008-10-04 23:56:55 +02:00
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WHERE d.parent_department = sd.id
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)
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SELECT * FROM subdepartment ORDER BY name;
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-- extract all departments under 'A' with "level" number
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WITH RECURSIVE subdepartment(level, id, parent_department, name) AS
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(
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-- non recursive term
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SELECT 1, * FROM department WHERE name = 'A'
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UNION ALL
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-- recursive term
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SELECT sd.level + 1, d.* FROM department AS d, subdepartment AS sd
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WHERE d.parent_department = sd.id
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)
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SELECT * FROM subdepartment ORDER BY name;
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-- extract all departments under 'A' with "level" number.
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-- Only shows level 2 or more
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WITH RECURSIVE subdepartment(level, id, parent_department, name) AS
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(
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-- non recursive term
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SELECT 1, * FROM department WHERE name = 'A'
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UNION ALL
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-- recursive term
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SELECT sd.level + 1, d.* FROM department AS d, subdepartment AS sd
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WHERE d.parent_department = sd.id
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)
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SELECT * FROM subdepartment WHERE level >= 2 ORDER BY name;
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-- "RECURSIVE" is ignored if the query has no self-reference
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WITH RECURSIVE subdepartment AS
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(
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-- note lack of recursive UNION structure
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SELECT * FROM department WHERE name = 'A'
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)
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SELECT * FROM subdepartment ORDER BY name;
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-- inside subqueries
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SELECT count(*) FROM (
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WITH RECURSIVE t(n) AS (
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SELECT 1 UNION ALL SELECT n + 1 FROM t WHERE n < 500
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)
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SELECT * FROM t) AS t WHERE n < (
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SELECT count(*) FROM (
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WITH RECURSIVE t(n) AS (
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SELECT 1 UNION ALL SELECT n + 1 FROM t WHERE n < 100
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)
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SELECT * FROM t WHERE n < 50000
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) AS t WHERE n < 100);
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-- use same CTE twice at different subquery levels
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WITH q1(x,y) AS (
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SELECT hundred, sum(ten) FROM tenk1 GROUP BY hundred
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)
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SELECT count(*) FROM q1 WHERE y > (SELECT sum(y)/100 FROM q1 qsub);
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-- via a VIEW
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CREATE TEMPORARY VIEW vsubdepartment AS
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WITH RECURSIVE subdepartment AS
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(
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-- non recursive term
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SELECT * FROM department WHERE name = 'A'
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UNION ALL
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-- recursive term
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SELECT d.* FROM department AS d, subdepartment AS sd
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WHERE d.parent_department = sd.id
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)
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SELECT * FROM subdepartment;
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SELECT * FROM vsubdepartment ORDER BY name;
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-- Check reverse listing
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SELECT pg_get_viewdef('vsubdepartment'::regclass);
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SELECT pg_get_viewdef('vsubdepartment'::regclass, true);
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2008-10-13 02:41:41 +02:00
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-- corner case in which sub-WITH gets initialized first
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with recursive q as (
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select * from department
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union all
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(with x as (select * from q)
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select * from x)
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)
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select * from q limit 24;
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with recursive q as (
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select * from department
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union all
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(with recursive x as (
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select * from department
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union all
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(select * from q union all select * from x)
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)
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select * from x)
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)
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select * from q limit 32;
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2008-10-04 23:56:55 +02:00
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-- recursive term has sub-UNION
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WITH RECURSIVE t(i,j) AS (
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VALUES (1,2)
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UNION ALL
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SELECT t2.i, t.j+1 FROM
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(SELECT 2 AS i UNION ALL SELECT 3 AS i) AS t2
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JOIN t ON (t2.i = t.i+1))
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SELECT * FROM t;
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--
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-- different tree example
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--
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CREATE TEMPORARY TABLE tree(
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id INTEGER PRIMARY KEY,
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parent_id INTEGER REFERENCES tree(id)
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);
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INSERT INTO tree
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VALUES (1, NULL), (2, 1), (3,1), (4,2), (5,2), (6,2), (7,3), (8,3),
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(9,4), (10,4), (11,7), (12,7), (13,7), (14, 9), (15,11), (16,11);
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--
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-- get all paths from "second level" nodes to leaf nodes
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--
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WITH RECURSIVE t(id, path) AS (
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VALUES(1,ARRAY[]::integer[])
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UNION ALL
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SELECT tree.id, t.path || tree.id
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FROM tree JOIN t ON (tree.parent_id = t.id)
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)
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SELECT t1.*, t2.* FROM t AS t1 JOIN t AS t2 ON
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(t1.path[1] = t2.path[1] AND
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array_upper(t1.path,1) = 1 AND
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array_upper(t2.path,1) > 1)
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ORDER BY t1.id, t2.id;
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-- just count 'em
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WITH RECURSIVE t(id, path) AS (
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VALUES(1,ARRAY[]::integer[])
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UNION ALL
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SELECT tree.id, t.path || tree.id
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FROM tree JOIN t ON (tree.parent_id = t.id)
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)
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SELECT t1.id, count(t2.*) FROM t AS t1 JOIN t AS t2 ON
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(t1.path[1] = t2.path[1] AND
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array_upper(t1.path,1) = 1 AND
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array_upper(t2.path,1) > 1)
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GROUP BY t1.id
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ORDER BY t1.id;
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2008-10-13 18:25:20 +02:00
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--
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-- test cycle detection
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--
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create temp table graph( f int, t int, label text );
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insert into graph values
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(1, 2, 'arc 1 -> 2'),
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(1, 3, 'arc 1 -> 3'),
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(2, 3, 'arc 2 -> 3'),
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(1, 4, 'arc 1 -> 4'),
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(4, 5, 'arc 4 -> 5'),
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(5, 1, 'arc 5 -> 1');
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with recursive search_graph(f, t, label, path, cycle) as (
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select *, array[row(g.f, g.t)], false from graph g
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union all
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2008-10-14 02:12:44 +02:00
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select g.*, path || row(g.f, g.t), row(g.f, g.t) = any(path)
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2008-10-13 18:25:20 +02:00
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from graph g, search_graph sg
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where g.f = sg.t and not cycle
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)
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select * from search_graph;
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2008-10-14 02:41:35 +02:00
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-- ordering by the path column has same effect as SEARCH DEPTH FIRST
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with recursive search_graph(f, t, label, path, cycle) as (
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select *, array[row(g.f, g.t)], false from graph g
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union all
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select g.*, path || row(g.f, g.t), row(g.f, g.t) = any(path)
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from graph g, search_graph sg
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where g.f = sg.t and not cycle
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)
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select * from search_graph order by path;
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2008-10-04 23:56:55 +02:00
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--
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-- test multiple WITH queries
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--
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WITH RECURSIVE
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y (id) AS (VALUES (1)),
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x (id) AS (SELECT * FROM y UNION ALL SELECT id+1 FROM x WHERE id < 5)
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SELECT * FROM x;
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-- forward reference OK
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WITH RECURSIVE
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x(id) AS (SELECT * FROM y UNION ALL SELECT id+1 FROM x WHERE id < 5),
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y(id) AS (values (1))
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SELECT * FROM x;
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WITH RECURSIVE
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x(id) AS
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(VALUES (1) UNION ALL SELECT id+1 FROM x WHERE id < 5),
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y(id) AS
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(VALUES (1) UNION ALL SELECT id+1 FROM y WHERE id < 10)
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SELECT y.*, x.* FROM y LEFT JOIN x USING (id);
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WITH RECURSIVE
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x(id) AS
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(VALUES (1) UNION ALL SELECT id+1 FROM x WHERE id < 5),
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y(id) AS
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(VALUES (1) UNION ALL SELECT id+1 FROM x WHERE id < 10)
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SELECT y.*, x.* FROM y LEFT JOIN x USING (id);
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WITH RECURSIVE
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x(id) AS
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(SELECT 1 UNION ALL SELECT id+1 FROM x WHERE id < 3 ),
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y(id) AS
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(SELECT * FROM x UNION ALL SELECT * FROM x),
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z(id) AS
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(SELECT * FROM x UNION ALL SELECT id+1 FROM z WHERE id < 10)
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SELECT * FROM z;
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WITH RECURSIVE
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x(id) AS
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(SELECT 1 UNION ALL SELECT id+1 FROM x WHERE id < 3 ),
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y(id) AS
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(SELECT * FROM x UNION ALL SELECT * FROM x),
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z(id) AS
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(SELECT * FROM y UNION ALL SELECT id+1 FROM z WHERE id < 10)
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SELECT * FROM z;
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--
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-- error cases
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--
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-- INTERSECT
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WITH RECURSIVE x(n) AS (SELECT 1 INTERSECT SELECT n+1 FROM x)
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SELECT * FROM x;
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WITH RECURSIVE x(n) AS (SELECT 1 INTERSECT ALL SELECT n+1 FROM x)
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SELECT * FROM x;
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-- EXCEPT
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WITH RECURSIVE x(n) AS (SELECT 1 EXCEPT SELECT n+1 FROM x)
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SELECT * FROM x;
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WITH RECURSIVE x(n) AS (SELECT 1 EXCEPT ALL SELECT n+1 FROM x)
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SELECT * FROM x;
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-- no non-recursive term
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WITH RECURSIVE x(n) AS (SELECT n FROM x)
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SELECT * FROM x;
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-- recursive term in the left hand side (strictly speaking, should allow this)
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WITH RECURSIVE x(n) AS (SELECT n FROM x UNION ALL SELECT 1)
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SELECT * FROM x;
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CREATE TEMPORARY TABLE y (a INTEGER);
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INSERT INTO y SELECT generate_series(1, 10);
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-- LEFT JOIN
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WITH RECURSIVE x(n) AS (SELECT a FROM y WHERE a = 1
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UNION ALL
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SELECT x.n+1 FROM y LEFT JOIN x ON x.n = y.a WHERE n < 10)
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SELECT * FROM x;
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-- RIGHT JOIN
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WITH RECURSIVE x(n) AS (SELECT a FROM y WHERE a = 1
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UNION ALL
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SELECT x.n+1 FROM x RIGHT JOIN y ON x.n = y.a WHERE n < 10)
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SELECT * FROM x;
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-- FULL JOIN
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WITH RECURSIVE x(n) AS (SELECT a FROM y WHERE a = 1
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UNION ALL
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SELECT x.n+1 FROM x FULL JOIN y ON x.n = y.a WHERE n < 10)
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SELECT * FROM x;
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-- subquery
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WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x
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WHERE n IN (SELECT * FROM x))
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SELECT * FROM x;
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-- aggregate functions
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WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT count(*) FROM x)
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SELECT * FROM x;
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WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT sum(n) FROM x)
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SELECT * FROM x;
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-- ORDER BY
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WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x ORDER BY 1)
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SELECT * FROM x;
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-- LIMIT/OFFSET
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WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x LIMIT 10 OFFSET 1)
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SELECT * FROM x;
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-- FOR UPDATE
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WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x FOR UPDATE)
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SELECT * FROM x;
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-- target list has a recursive query name
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WITH RECURSIVE x(id) AS (values (1)
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UNION ALL
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SELECT (SELECT * FROM x) FROM x WHERE id < 5
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) SELECT * FROM x;
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-- mutual recursive query (not implemented)
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WITH RECURSIVE
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x (id) AS (SELECT 1 UNION ALL SELECT id+1 FROM y WHERE id < 5),
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y (id) AS (SELECT 1 UNION ALL SELECT id+1 FROM x WHERE id < 5)
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SELECT * FROM x;
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-- non-linear recursion is not allowed
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WITH RECURSIVE foo(i) AS
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|
(values (1)
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UNION ALL
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(SELECT i+1 FROM foo WHERE i < 10
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UNION ALL
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SELECT i+1 FROM foo WHERE i < 5)
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) SELECT * FROM foo;
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WITH RECURSIVE foo(i) AS
|
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|
|
(values (1)
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|
UNION ALL
|
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|
SELECT * FROM
|
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|
(SELECT i+1 FROM foo WHERE i < 10
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UNION ALL
|
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|
SELECT i+1 FROM foo WHERE i < 5) AS t
|
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|
) SELECT * FROM foo;
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|
WITH RECURSIVE foo(i) AS
|
|
|
|
(values (1)
|
|
|
|
UNION ALL
|
|
|
|
(SELECT i+1 FROM foo WHERE i < 10
|
|
|
|
EXCEPT
|
|
|
|
SELECT i+1 FROM foo WHERE i < 5)
|
|
|
|
) SELECT * FROM foo;
|
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|
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|
|
|
WITH RECURSIVE foo(i) AS
|
|
|
|
(values (1)
|
|
|
|
UNION ALL
|
|
|
|
(SELECT i+1 FROM foo WHERE i < 10
|
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|
|
INTERSECT
|
|
|
|
SELECT i+1 FROM foo WHERE i < 5)
|
|
|
|
) SELECT * FROM foo;
|
|
|
|
|
|
|
|
-- Wrong type induced from non-recursive term
|
|
|
|
WITH RECURSIVE foo(i) AS
|
|
|
|
(SELECT i FROM (VALUES(1),(2)) t(i)
|
|
|
|
UNION ALL
|
|
|
|
SELECT (i+1)::numeric(10,0) FROM foo WHERE i < 10)
|
|
|
|
SELECT * FROM foo;
|
|
|
|
|
|
|
|
-- rejects different typmod, too (should we allow this?)
|
|
|
|
WITH RECURSIVE foo(i) AS
|
|
|
|
(SELECT i::numeric(3,0) FROM (VALUES(1),(2)) t(i)
|
|
|
|
UNION ALL
|
|
|
|
SELECT (i+1)::numeric(10,0) FROM foo WHERE i < 10)
|
|
|
|
SELECT * FROM foo;
|