Add docs and regression test about sorting the output of a recursive query in

[postgresql] / src / test / regress / expected / with.out

--
-- Tests for common table expressions (WITH query, ... SELECT ...)
--
-- Basic WITH
WITH q1(x,y) AS (SELECT 1,2)
SELECT * FROM q1, q1 AS q2;
 x | y | x | y 
---+---+---+---
 1 | 2 | 1 | 2
(1 row)

-- Multiple uses are evaluated only once
SELECT count(*) FROM (
  WITH q1(x) AS (SELECT random() FROM generate_series(1, 5))
    SELECT * FROM q1
  UNION
    SELECT * FROM q1
) ss;
 count 
-------
     5
(1 row)

-- WITH RECURSIVE
-- sum of 1..100
WITH RECURSIVE t(n) AS (
    VALUES (1)
UNION ALL
    SELECT n+1 FROM t WHERE n < 100
)
SELECT sum(n) FROM t;
 sum  
------
 5050
(1 row)

WITH RECURSIVE t(n) AS (
    SELECT (VALUES(1))
UNION ALL
    SELECT n+1 FROM t WHERE n < 5
)
SELECT * FROM t;
 n 
---
 1
 2
 3
 4
 5
(5 rows)

-- This is an infinite loop with UNION ALL, but not with UNION
WITH RECURSIVE t(n) AS (
    SELECT 1
UNION
    SELECT 10-n FROM t)
SELECT * FROM t;
 n 
---
 1
 9
(2 rows)

-- This'd be an infinite loop, but outside query reads only as much as needed
WITH RECURSIVE t(n) AS (
    VALUES (1)
UNION ALL
    SELECT n+1 FROM t)
SELECT * FROM t LIMIT 10;
 n  
----
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
(10 rows)

-- UNION case should have same property
WITH RECURSIVE t(n) AS (
    SELECT 1
UNION
    SELECT n+1 FROM t)
SELECT * FROM t LIMIT 10;
 n  
----
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
(10 rows)

-- Test behavior with an unknown-type literal in the WITH
WITH q AS (SELECT 'foo' AS x)
SELECT x, x IS OF (unknown) as is_unknown FROM q;
  x  | is_unknown 
-----+------------
 foo | t
(1 row)

WITH RECURSIVE t(n) AS (
    SELECT 'foo'
UNION ALL
    SELECT n || ' bar' FROM t WHERE length(n) < 20
)
SELECT n, n IS OF (text) as is_text FROM t;
            n            | is_text 
-------------------------+---------
 foo                     | t
 foo bar                 | t
 foo bar bar             | t
 foo bar bar bar         | t
 foo bar bar bar bar     | t
 foo bar bar bar bar bar | t
(6 rows)

--
-- Some examples with a tree
--
-- department structure represented here is as follows:
--
-- ROOT-+->A-+->B-+->C
--      |         |
--      |         +->D-+->F
--      +->E-+->G
CREATE TEMP TABLE department (
        id INTEGER PRIMARY KEY,  -- department ID
        parent_department INTEGER REFERENCES department, -- upper department ID
        name TEXT -- department name
);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "department_pkey" for table "department"
INSERT INTO department VALUES (0, NULL, 'ROOT');
INSERT INTO department VALUES (1, 0, 'A');
INSERT INTO department VALUES (2, 1, 'B');
INSERT INTO department VALUES (3, 2, 'C');
INSERT INTO department VALUES (4, 2, 'D');
INSERT INTO department VALUES (5, 0, 'E');
INSERT INTO department VALUES (6, 4, 'F');
INSERT INTO department VALUES (7, 5, 'G');
-- extract all departments under 'A'. Result should be A, B, C, D and F
WITH RECURSIVE subdepartment AS
(
        -- non recursive term
        SELECT name as root_name, * FROM department WHERE name = 'A'
        UNION ALL
        -- recursive term
        SELECT sd.root_name, d.* FROM department AS d, subdepartment AS sd
                WHERE d.parent_department = sd.id
)
SELECT * FROM subdepartment ORDER BY name;
 root_name | id | parent_department | name 
-----------+----+-------------------+------
 A         |  1 |                 0 | A
 A         |  2 |                 1 | B
 A         |  3 |                 2 | C
 A         |  4 |                 2 | D
 A         |  6 |                 4 | F
(5 rows)

-- extract all departments under 'A' with "level" number
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)

-- extract all departments under 'A' with "level" number.
-- Only shows level 2 or more
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 WHERE level >= 2 ORDER BY name;
 level | id | parent_department | name 
-------+----+-------------------+------
     2 |  2 |                 1 | B
     3 |  3 |                 2 | C
     3 |  4 |                 2 | D
     4 |  6 |                 4 | F
(4 rows)

-- "RECURSIVE" is ignored if the query has no self-reference
WITH RECURSIVE subdepartment AS
(
        -- note lack of recursive UNION structure
        SELECT * FROM department WHERE name = 'A'
)
SELECT * FROM subdepartment ORDER BY name;
 id | parent_department | name 
----+-------------------+------
  1 |                 0 | A
(1 row)

-- inside subqueries
SELECT count(*) FROM (
    WITH RECURSIVE t(n) AS (
        SELECT 1 UNION ALL SELECT n + 1 FROM t WHERE n < 500
    )
    SELECT * FROM t) AS t WHERE n < (
        SELECT count(*) FROM (
            WITH RECURSIVE t(n) AS (
                   SELECT 1 UNION ALL SELECT n + 1 FROM t WHERE n < 100
                )
            SELECT * FROM t WHERE n < 50000
         ) AS t WHERE n < 100);
 count 
-------
    98
(1 row)

-- use same CTE twice at different subquery levels
WITH q1(x,y) AS (
    SELECT hundred, sum(ten) FROM tenk1 GROUP BY hundred
  )
SELECT count(*) FROM q1 WHERE y > (SELECT sum(y)/100 FROM q1 qsub);
 count 
-------
    50
(1 row)

-- via a VIEW
CREATE TEMPORARY VIEW vsubdepartment AS
        WITH RECURSIVE subdepartment AS
        (
                 -- non recursive term
                SELECT * FROM department WHERE name = 'A'
                UNION ALL
                -- recursive term
                SELECT d.* FROM department AS d, subdepartment AS sd
                        WHERE d.parent_department = sd.id
        )
        SELECT * FROM subdepartment;
SELECT * FROM vsubdepartment ORDER BY name;
 id | parent_department | name 
----+-------------------+------
  1 |                 0 | A
  2 |                 1 | B
  3 |                 2 | C
  4 |                 2 | D
  6 |                 4 | F
(5 rows)

-- Check reverse listing
SELECT pg_get_viewdef('vsubdepartment'::regclass);
                                                                                                                                                                                    pg_get_viewdef                                                                                                                                                                                     
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 WITH RECURSIVE subdepartment AS (SELECT department.id, department.parent_department, department.name FROM department WHERE (department.name = 'A'::text) UNION ALL SELECT d.id, d.parent_department, d.name FROM department d, subdepartment sd WHERE (d.parent_department = sd.id)) SELECT subdepartment.id, subdepartment.parent_department, subdepartment.name FROM subdepartment;
(1 row)

SELECT pg_get_viewdef('vsubdepartment'::regclass, true);
                                    pg_get_viewdef                                    
--------------------------------------------------------------------------------------
  WITH RECURSIVE subdepartment AS (
                  SELECT department.id, department.parent_department, department.name
                    FROM department
                   WHERE department.name = 'A'::text
         UNION ALL 
                  SELECT d.id, d.parent_department, d.name
                    FROM department d, subdepartment sd
                   WHERE d.parent_department = sd.id
         )
  SELECT subdepartment.id, subdepartment.parent_department, subdepartment.name
    FROM subdepartment;
(1 row)

-- corner case in which sub-WITH gets initialized first
with recursive q as (
      select * from department
    union all
      (with x as (select * from q)
       select * from x)
    )
select * from q limit 24;
 id | parent_department | name 
----+-------------------+------
  0 |                   | ROOT
  1 |                 0 | A
  2 |                 1 | B
  3 |                 2 | C
  4 |                 2 | D
  5 |                 0 | E
  6 |                 4 | F
  7 |                 5 | G
  0 |                   | ROOT
  1 |                 0 | A
  2 |                 1 | B
  3 |                 2 | C
  4 |                 2 | D
  5 |                 0 | E
  6 |                 4 | F
  7 |                 5 | G
  0 |                   | ROOT
  1 |                 0 | A
  2 |                 1 | B
  3 |                 2 | C
  4 |                 2 | D
  5 |                 0 | E
  6 |                 4 | F
  7 |                 5 | G
(24 rows)

with recursive q as (
      select * from department
    union all
      (with recursive x as (
           select * from department
         union all
           (select * from q union all select * from x)
        )
       select * from x)
    )
select * from q limit 32;
 id | parent_department | name 
----+-------------------+------
  0 |                   | ROOT
  1 |                 0 | A
  2 |                 1 | B
  3 |                 2 | C
  4 |                 2 | D
  5 |                 0 | E
  6 |                 4 | F
  7 |                 5 | G
  0 |                   | ROOT
  1 |                 0 | A
  2 |                 1 | B
  3 |                 2 | C
  4 |                 2 | D
  5 |                 0 | E
  6 |                 4 | F
  7 |                 5 | G
  0 |                   | ROOT
  1 |                 0 | A
  2 |                 1 | B
  3 |                 2 | C
  4 |                 2 | D
  5 |                 0 | E
  6 |                 4 | F
  7 |                 5 | G
  0 |                   | ROOT
  1 |                 0 | A
  2 |                 1 | B
  3 |                 2 | C
  4 |                 2 | D
  5 |                 0 | E
  6 |                 4 | F
  7 |                 5 | G
(32 rows)

-- recursive term has sub-UNION
WITH RECURSIVE t(i,j) AS (
        VALUES (1,2)
        UNION ALL
        SELECT t2.i, t.j+1 FROM
                (SELECT 2 AS i UNION ALL SELECT 3 AS i) AS t2
                JOIN t ON (t2.i = t.i+1))
        SELECT * FROM t;
 i | j 
---+---
 1 | 2
 2 | 3
 3 | 4
(3 rows)

--
-- different tree example
--
CREATE TEMPORARY TABLE tree(
    id INTEGER PRIMARY KEY,
    parent_id INTEGER REFERENCES tree(id)
);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "tree_pkey" for table "tree"
INSERT INTO tree
VALUES (1, NULL), (2, 1), (3,1), (4,2), (5,2), (6,2), (7,3), (8,3),
       (9,4), (10,4), (11,7), (12,7), (13,7), (14, 9), (15,11), (16,11);
--
-- get all paths from "second level" nodes to leaf nodes
--
WITH RECURSIVE t(id, path) AS (
    VALUES(1,ARRAY[]::integer[])
UNION ALL
    SELECT tree.id, t.path || tree.id
    FROM tree JOIN t ON (tree.parent_id = t.id)
)
SELECT t1.*, t2.* FROM t AS t1 JOIN t AS t2 ON
        (t1.path[1] = t2.path[1] AND
        array_upper(t1.path,1) = 1 AND
        array_upper(t2.path,1) > 1)
        ORDER BY t1.id, t2.id;
 id | path | id |    path     
----+------+----+-------------
  2 | {2}  |  4 | {2,4}
  2 | {2}  |  5 | {2,5}
  2 | {2}  |  6 | {2,6}
  2 | {2}  |  9 | {2,4,9}
  2 | {2}  | 10 | {2,4,10}
  2 | {2}  | 14 | {2,4,9,14}
  3 | {3}  |  7 | {3,7}
  3 | {3}  |  8 | {3,8}
  3 | {3}  | 11 | {3,7,11}
  3 | {3}  | 12 | {3,7,12}
  3 | {3}  | 13 | {3,7,13}
  3 | {3}  | 15 | {3,7,11,15}
  3 | {3}  | 16 | {3,7,11,16}
(13 rows)

-- just count 'em
WITH RECURSIVE t(id, path) AS (
    VALUES(1,ARRAY[]::integer[])
UNION ALL
    SELECT tree.id, t.path || tree.id
    FROM tree JOIN t ON (tree.parent_id = t.id)
)
SELECT t1.id, count(t2.*) FROM t AS t1 JOIN t AS t2 ON
        (t1.path[1] = t2.path[1] AND
        array_upper(t1.path,1) = 1 AND
        array_upper(t2.path,1) > 1)
        GROUP BY t1.id
        ORDER BY t1.id;
 id | count 
----+-------
  2 |     6
  3 |     7
(2 rows)

--
-- test cycle detection
--
create temp table graph( f int, t int, label text );
insert into graph values
        (1, 2, 'arc 1 -> 2'),
        (1, 3, 'arc 1 -> 3'),
        (2, 3, 'arc 2 -> 3'),
        (1, 4, 'arc 1 -> 4'),
        (4, 5, 'arc 4 -> 5'),
        (5, 1, 'arc 5 -> 1');
with recursive search_graph(f, t, label, path, cycle) as (
        select *, array[row(g.f, g.t)], false from graph g
        union all
        select g.*, path || row(g.f, g.t), row(g.f, g.t) = any(path)
        from graph g, search_graph sg
        where g.f = sg.t and not cycle
)
select * from search_graph;
 f | t |   label    |                   path                    | cycle 
---+---+------------+-------------------------------------------+-------
 1 | 2 | arc 1 -> 2 | {"(1,2)"}                                 | f
 1 | 3 | arc 1 -> 3 | {"(1,3)"}                                 | f
 2 | 3 | arc 2 -> 3 | {"(2,3)"}                                 | f
 1 | 4 | arc 1 -> 4 | {"(1,4)"}                                 | f
 4 | 5 | arc 4 -> 5 | {"(4,5)"}                                 | f
 5 | 1 | arc 5 -> 1 | {"(5,1)"}                                 | f
 1 | 2 | arc 1 -> 2 | {"(5,1)","(1,2)"}                         | f
 1 | 3 | arc 1 -> 3 | {"(5,1)","(1,3)"}                         | f
 1 | 4 | arc 1 -> 4 | {"(5,1)","(1,4)"}                         | f
 2 | 3 | arc 2 -> 3 | {"(1,2)","(2,3)"}                         | f
 4 | 5 | arc 4 -> 5 | {"(1,4)","(4,5)"}                         | f
 5 | 1 | arc 5 -> 1 | {"(4,5)","(5,1)"}                         | f
 1 | 2 | arc 1 -> 2 | {"(4,5)","(5,1)","(1,2)"}                 | f
 1 | 3 | arc 1 -> 3 | {"(4,5)","(5,1)","(1,3)"}                 | f
 1 | 4 | arc 1 -> 4 | {"(4,5)","(5,1)","(1,4)"}                 | f
 2 | 3 | arc 2 -> 3 | {"(5,1)","(1,2)","(2,3)"}                 | f
 4 | 5 | arc 4 -> 5 | {"(5,1)","(1,4)","(4,5)"}                 | f
 5 | 1 | arc 5 -> 1 | {"(1,4)","(4,5)","(5,1)"}                 | f
 1 | 2 | arc 1 -> 2 | {"(1,4)","(4,5)","(5,1)","(1,2)"}         | f
 1 | 3 | arc 1 -> 3 | {"(1,4)","(4,5)","(5,1)","(1,3)"}         | f
 1 | 4 | arc 1 -> 4 | {"(1,4)","(4,5)","(5,1)","(1,4)"}         | t
 2 | 3 | arc 2 -> 3 | {"(4,5)","(5,1)","(1,2)","(2,3)"}         | f
 4 | 5 | arc 4 -> 5 | {"(4,5)","(5,1)","(1,4)","(4,5)"}         | t
 5 | 1 | arc 5 -> 1 | {"(5,1)","(1,4)","(4,5)","(5,1)"}         | t
 2 | 3 | arc 2 -> 3 | {"(1,4)","(4,5)","(5,1)","(1,2)","(2,3)"} | f
(25 rows)

-- ordering by the path column has same effect as SEARCH DEPTH FIRST
with recursive search_graph(f, t, label, path, cycle) as (
        select *, array[row(g.f, g.t)], false from graph g
        union all
        select g.*, path || row(g.f, g.t), row(g.f, g.t) = any(path)
        from graph g, search_graph sg
        where g.f = sg.t and not cycle
)
select * from search_graph order by path;
 f | t |   label    |                   path                    | cycle 
---+---+------------+-------------------------------------------+-------
 1 | 2 | arc 1 -> 2 | {"(1,2)"}                                 | f
 2 | 3 | arc 2 -> 3 | {"(1,2)","(2,3)"}                         | f
 1 | 3 | arc 1 -> 3 | {"(1,3)"}                                 | f
 1 | 4 | arc 1 -> 4 | {"(1,4)"}                                 | f
 4 | 5 | arc 4 -> 5 | {"(1,4)","(4,5)"}                         | f
 5 | 1 | arc 5 -> 1 | {"(1,4)","(4,5)","(5,1)"}                 | f
 1 | 2 | arc 1 -> 2 | {"(1,4)","(4,5)","(5,1)","(1,2)"}         | f
 2 | 3 | arc 2 -> 3 | {"(1,4)","(4,5)","(5,1)","(1,2)","(2,3)"} | f
 1 | 3 | arc 1 -> 3 | {"(1,4)","(4,5)","(5,1)","(1,3)"}         | f
 1 | 4 | arc 1 -> 4 | {"(1,4)","(4,5)","(5,1)","(1,4)"}         | t
 2 | 3 | arc 2 -> 3 | {"(2,3)"}                                 | f
 4 | 5 | arc 4 -> 5 | {"(4,5)"}                                 | f
 5 | 1 | arc 5 -> 1 | {"(4,5)","(5,1)"}                         | f
 1 | 2 | arc 1 -> 2 | {"(4,5)","(5,1)","(1,2)"}                 | f
 2 | 3 | arc 2 -> 3 | {"(4,5)","(5,1)","(1,2)","(2,3)"}         | f
 1 | 3 | arc 1 -> 3 | {"(4,5)","(5,1)","(1,3)"}                 | f
 1 | 4 | arc 1 -> 4 | {"(4,5)","(5,1)","(1,4)"}                 | f
 4 | 5 | arc 4 -> 5 | {"(4,5)","(5,1)","(1,4)","(4,5)"}         | t
 5 | 1 | arc 5 -> 1 | {"(5,1)"}                                 | f
 1 | 2 | arc 1 -> 2 | {"(5,1)","(1,2)"}                         | f
 2 | 3 | arc 2 -> 3 | {"(5,1)","(1,2)","(2,3)"}                 | f
 1 | 3 | arc 1 -> 3 | {"(5,1)","(1,3)"}                         | f
 1 | 4 | arc 1 -> 4 | {"(5,1)","(1,4)"}                         | f
 4 | 5 | arc 4 -> 5 | {"(5,1)","(1,4)","(4,5)"}                 | f
 5 | 1 | arc 5 -> 1 | {"(5,1)","(1,4)","(4,5)","(5,1)"}         | t
(25 rows)

--
-- test multiple WITH queries
--
WITH RECURSIVE
  y (id) AS (VALUES (1)),
  x (id) AS (SELECT * FROM y UNION ALL SELECT id+1 FROM x WHERE id < 5)
SELECT * FROM x;
 id 
----
  1
  2
  3
  4
  5
(5 rows)

-- forward reference OK
WITH RECURSIVE
    x(id) AS (SELECT * FROM y UNION ALL SELECT id+1 FROM x WHERE id < 5),
    y(id) AS (values (1))
 SELECT * FROM x;
 id 
----
  1
  2
  3
  4
  5
(5 rows)

WITH RECURSIVE
   x(id) AS
     (VALUES (1) UNION ALL SELECT id+1 FROM x WHERE id < 5),
   y(id) AS
     (VALUES (1) UNION ALL SELECT id+1 FROM y WHERE id < 10)
 SELECT y.*, x.* FROM y LEFT JOIN x USING (id);
 id | id 
----+----
  1 |  1
  2 |  2
  3 |  3
  4 |  4
  5 |  5
  6 |   
  7 |   
  8 |   
  9 |   
 10 |   
(10 rows)

WITH RECURSIVE
   x(id) AS
     (VALUES (1) UNION ALL SELECT id+1 FROM x WHERE id < 5),
   y(id) AS
     (VALUES (1) UNION ALL SELECT id+1 FROM x WHERE id < 10)
 SELECT y.*, x.* FROM y LEFT JOIN x USING (id);
 id | id 
----+----
  1 |  1
  2 |  2
  3 |  3
  4 |  4
  5 |  5
  6 |   
(6 rows)

WITH RECURSIVE
   x(id) AS
     (SELECT 1 UNION ALL SELECT id+1 FROM x WHERE id < 3 ),
   y(id) AS
     (SELECT * FROM x UNION ALL SELECT * FROM x),
   z(id) AS
     (SELECT * FROM x UNION ALL SELECT id+1 FROM z WHERE id < 10)
 SELECT * FROM z;
 id 
----
  1
  2
  3
  2
  3
  4
  3
  4
  5
  4
  5
  6
  5
  6
  7
  6
  7
  8
  7
  8
  9
  8
  9
 10
  9
 10
 10
(27 rows)

WITH RECURSIVE
   x(id) AS
     (SELECT 1 UNION ALL SELECT id+1 FROM x WHERE id < 3 ),
   y(id) AS
     (SELECT * FROM x UNION ALL SELECT * FROM x),
   z(id) AS
     (SELECT * FROM y UNION ALL SELECT id+1 FROM z WHERE id < 10)
 SELECT * FROM z;
 id 
----
  1
  2
  3
  1
  2
  3
  2
  3
  4
  2
  3
  4
  3
  4
  5
  3
  4
  5
  4
  5
  6
  4
  5
  6
  5
  6
  7
  5
  6
  7
  6
  7
  8
  6
  7
  8
  7
  8
  9
  7
  8
  9
  8
  9
 10
  8
  9
 10
  9
 10
  9
 10
 10
 10
(54 rows)

--
-- error cases
--
-- INTERSECT
WITH RECURSIVE x(n) AS (SELECT 1 INTERSECT SELECT n+1 FROM x)
        SELECT * FROM x;
ERROR:  recursive query "x" does not have the form non-recursive-term UNION [ALL] recursive-term
LINE 1: WITH RECURSIVE x(n) AS (SELECT 1 INTERSECT SELECT n+1 FROM x...
                       ^
WITH RECURSIVE x(n) AS (SELECT 1 INTERSECT ALL SELECT n+1 FROM x)
        SELECT * FROM x;
ERROR:  recursive query "x" does not have the form non-recursive-term UNION [ALL] recursive-term
LINE 1: WITH RECURSIVE x(n) AS (SELECT 1 INTERSECT ALL SELECT n+1 FR...
                       ^
-- EXCEPT
WITH RECURSIVE x(n) AS (SELECT 1 EXCEPT SELECT n+1 FROM x)
        SELECT * FROM x;
ERROR:  recursive query "x" does not have the form non-recursive-term UNION [ALL] recursive-term
LINE 1: WITH RECURSIVE x(n) AS (SELECT 1 EXCEPT SELECT n+1 FROM x)
                       ^
WITH RECURSIVE x(n) AS (SELECT 1 EXCEPT ALL SELECT n+1 FROM x)
        SELECT * FROM x;
ERROR:  recursive query "x" does not have the form non-recursive-term UNION [ALL] recursive-term
LINE 1: WITH RECURSIVE x(n) AS (SELECT 1 EXCEPT ALL SELECT n+1 FROM ...
                       ^
-- no non-recursive term
WITH RECURSIVE x(n) AS (SELECT n FROM x)
        SELECT * FROM x;
ERROR:  recursive query "x" does not have the form non-recursive-term UNION [ALL] recursive-term
LINE 1: WITH RECURSIVE x(n) AS (SELECT n FROM x)
                       ^
-- recursive term in the left hand side (strictly speaking, should allow this)
WITH RECURSIVE x(n) AS (SELECT n FROM x UNION ALL SELECT 1)
        SELECT * FROM x;
ERROR:  recursive reference to query "x" must not appear within its non-recursive term
LINE 1: WITH RECURSIVE x(n) AS (SELECT n FROM x UNION ALL SELECT 1)
                                              ^
CREATE TEMPORARY TABLE y (a INTEGER);
INSERT INTO y SELECT generate_series(1, 10);
-- LEFT JOIN
WITH RECURSIVE x(n) AS (SELECT a FROM y WHERE a = 1
        UNION ALL
        SELECT x.n+1 FROM y LEFT JOIN x ON x.n = y.a WHERE n < 10)
SELECT * FROM x;
ERROR:  recursive reference to query "x" must not appear within an outer join
LINE 3:  SELECT x.n+1 FROM y LEFT JOIN x ON x.n = y.a WHERE n < 10)
                                       ^
-- RIGHT JOIN
WITH RECURSIVE x(n) AS (SELECT a FROM y WHERE a = 1
        UNION ALL
        SELECT x.n+1 FROM x RIGHT JOIN y ON x.n = y.a WHERE n < 10)
SELECT * FROM x;
ERROR:  recursive reference to query "x" must not appear within an outer join
LINE 3:  SELECT x.n+1 FROM x RIGHT JOIN y ON x.n = y.a WHERE n < 10)
                           ^
-- FULL JOIN
WITH RECURSIVE x(n) AS (SELECT a FROM y WHERE a = 1
        UNION ALL
        SELECT x.n+1 FROM x FULL JOIN y ON x.n = y.a WHERE n < 10)
SELECT * FROM x;
ERROR:  recursive reference to query "x" must not appear within an outer join
LINE 3:  SELECT x.n+1 FROM x FULL JOIN y ON x.n = y.a WHERE n < 10)
                           ^
-- subquery
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x
                          WHERE n IN (SELECT * FROM x))
  SELECT * FROM x;
ERROR:  recursive reference to query "x" must not appear within a subquery
LINE 2:                           WHERE n IN (SELECT * FROM x))
                                                            ^
-- aggregate functions
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT count(*) FROM x)
  SELECT * FROM x;
ERROR:  aggregates not allowed in a recursive query's recursive term
LINE 1: WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT count(*) F...
                                                          ^
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT sum(n) FROM x)
  SELECT * FROM x;
ERROR:  aggregates not allowed in a recursive query's recursive term
LINE 1: WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT sum(n) FRO...
                                                          ^
-- ORDER BY
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x ORDER BY 1)
  SELECT * FROM x;
ERROR:  ORDER BY in a recursive query is not implemented
LINE 1: ...VE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x ORDER BY 1)
                                                                     ^
-- LIMIT/OFFSET
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x LIMIT 10 OFFSET 1)
  SELECT * FROM x;
ERROR:  OFFSET in a recursive query is not implemented
LINE 1: ... AS (SELECT 1 UNION ALL SELECT n+1 FROM x LIMIT 10 OFFSET 1)
                                                                     ^
-- FOR UPDATE
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x FOR UPDATE)
  SELECT * FROM x;
ERROR:  FOR UPDATE/SHARE in a recursive query is not implemented
-- target list has a recursive query name
WITH RECURSIVE x(id) AS (values (1)
    UNION ALL
    SELECT (SELECT * FROM x) FROM x WHERE id < 5
) SELECT * FROM x;
ERROR:  recursive reference to query "x" must not appear within a subquery
LINE 3:     SELECT (SELECT * FROM x) FROM x WHERE id < 5
                                  ^
-- mutual recursive query (not implemented)
WITH RECURSIVE
  x (id) AS (SELECT 1 UNION ALL SELECT id+1 FROM y WHERE id < 5),
  y (id) AS (SELECT 1 UNION ALL SELECT id+1 FROM x WHERE id < 5)
SELECT * FROM x;
ERROR:  mutual recursion between WITH items is not implemented
LINE 2:   x (id) AS (SELECT 1 UNION ALL SELECT id+1 FROM y WHERE id ...
          ^
-- non-linear recursion is not allowed
WITH RECURSIVE foo(i) AS
    (values (1)
    UNION ALL
       (SELECT i+1 FROM foo WHERE i < 10
          UNION ALL
       SELECT i+1 FROM foo WHERE i < 5)
) SELECT * FROM foo;
ERROR:  recursive reference to query "foo" must not appear more than once
LINE 6:        SELECT i+1 FROM foo WHERE i < 5)
                               ^
WITH RECURSIVE foo(i) AS
    (values (1)
    UNION ALL
           SELECT * FROM
       (SELECT i+1 FROM foo WHERE i < 10
          UNION ALL
       SELECT i+1 FROM foo WHERE i < 5) AS t
) SELECT * FROM foo;
ERROR:  recursive reference to query "foo" must not appear more than once
LINE 7:        SELECT i+1 FROM foo WHERE i < 5) AS t
                               ^
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;
ERROR:  recursive reference to query "foo" must not appear within EXCEPT
LINE 6:        SELECT i+1 FROM foo WHERE i < 5)
                               ^
WITH RECURSIVE foo(i) AS
    (values (1)
    UNION ALL
       (SELECT i+1 FROM foo WHERE i < 10
          INTERSECT
       SELECT i+1 FROM foo WHERE i < 5)
) SELECT * FROM foo;
ERROR:  recursive reference to query "foo" must not appear more than once
LINE 6:        SELECT i+1 FROM foo WHERE i < 5)
                               ^
-- 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;
ERROR:  recursive query "foo" column 1 has type integer in non-recursive term but type numeric overall
LINE 2:    (SELECT i FROM (VALUES(1),(2)) t(i)
                   ^
HINT:  Cast the output of the non-recursive term to the correct type.
-- 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;
ERROR:  recursive query "foo" column 1 has type numeric(3,0) in non-recursive term but type numeric overall
LINE 2:    (SELECT i::numeric(3,0) FROM (VALUES(1),(2)) t(i)
                   ^
HINT:  Cast the output of the non-recursive term to the correct type.