-- -- 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) -- this variant tickled a whole-row-variable bug in 8.4devel 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, t2.path, t2 FROM t AS t1 JOIN t AS t2 ON (t1.id=t2.id); id | path | t2 ----+-------------+-------------------- 1 | {} | (1,{}) 2 | {2} | (2,{2}) 3 | {3} | (3,{3}) 4 | {2,4} | (4,"{2,4}") 5 | {2,5} | (5,"{2,5}") 6 | {2,6} | (6,"{2,6}") 7 | {3,7} | (7,"{3,7}") 8 | {3,8} | (8,"{3,8}") 9 | {2,4,9} | (9,"{2,4,9}") 10 | {2,4,10} | (10,"{2,4,10}") 11 | {3,7,11} | (11,"{3,7,11}") 12 | {3,7,12} | (12,"{3,7,12}") 13 | {3,7,13} | (13,"{3,7,13}") 14 | {2,4,9,14} | (14,"{2,4,9,14}") 15 | {3,7,11,15} | (15,"{3,7,11,15}") 16 | {3,7,11,16} | (16,"{3,7,11,16}") (16 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) -- -- Test WITH attached to a data-modifying statement -- CREATE TEMPORARY TABLE y (a INTEGER); INSERT INTO y SELECT generate_series(1, 10); WITH t AS ( SELECT a FROM y ) INSERT INTO y SELECT a+20 FROM t RETURNING *; a ---- 21 22 23 24 25 26 27 28 29 30 (10 rows) SELECT * FROM y; a ---- 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 (20 rows) WITH t AS ( SELECT a FROM y ) UPDATE y SET a = y.a-10 FROM t WHERE y.a > 20 AND t.a = y.a RETURNING y.a; a ---- 11 12 13 14 15 16 17 18 19 20 (10 rows) SELECT * FROM y; a ---- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 (20 rows) WITH RECURSIVE t(a) AS ( SELECT 11 UNION ALL SELECT a+1 FROM t WHERE a < 50 ) DELETE FROM y USING t WHERE t.a = y.a RETURNING y.a; a ---- 11 12 13 14 15 16 17 18 19 20 (10 rows) SELECT * FROM y; a ---- 1 2 3 4 5 6 7 8 9 10 (10 rows) DROP TABLE y; -- -- 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: aggregate functions 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: aggregate functions 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. -- disallow OLD/NEW reference in CTE CREATE TEMPORARY TABLE x (n integer); CREATE RULE r2 AS ON UPDATE TO x DO INSTEAD WITH t AS (SELECT OLD.*) UPDATE y SET a = t.n FROM t; ERROR: cannot refer to OLD within WITH query -- -- test for bug #4902 -- with cte(foo) as ( values(42) ) values((select foo from cte)); column1 --------- 42 (1 row) with cte(foo) as ( select 42 ) select * from ((select foo from cte)) q; foo ----- 42 (1 row) -- test CTE referencing an outer-level variable (to see that changed-parameter -- signaling still works properly after fixing this bug) select ( with cte(foo) as ( values(f1) ) select (select foo from cte) ) from int4_tbl; ?column? ------------- 0 123456 -123456 2147483647 -2147483647 (5 rows) select ( with cte(foo) as ( values(f1) ) values((select foo from cte)) ) from int4_tbl; ?column? ------------- 0 123456 -123456 2147483647 -2147483647 (5 rows) -- -- test for nested-recursive-WITH bug -- WITH RECURSIVE t(j) AS ( WITH RECURSIVE s(i) AS ( VALUES (1) UNION ALL SELECT i+1 FROM s WHERE i < 10 ) SELECT i FROM s UNION ALL SELECT j+1 FROM t WHERE j < 10 ) SELECT * FROM t; j ---- 1 2 3 4 5 6 7 8 9 10 2 3 4 5 6 7 8 9 10 3 4 5 6 7 8 9 10 4 5 6 7 8 9 10 5 6 7 8 9 10 6 7 8 9 10 7 8 9 10 8 9 10 9 10 10 (55 rows) -- -- Data-modifying statements in WITH -- -- INSERT ... RETURNING WITH t AS ( INSERT INTO y VALUES (11), (12), (13), (14), (15), (16), (17), (18), (19), (20) RETURNING * ) SELECT * FROM t; a ---- 11 12 13 14 15 16 17 18 19 20 (10 rows) SELECT * FROM y; a ---- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 (20 rows) -- UPDATE ... RETURNING WITH t AS ( UPDATE y SET a=a+1 RETURNING * ) SELECT * FROM t; a ---- 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 (20 rows) SELECT * FROM y; a ---- 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 (20 rows) -- DELETE ... RETURNING WITH t AS ( DELETE FROM y WHERE a <= 10 RETURNING * ) SELECT * FROM t; a ---- 2 3 4 5 6 7 8 9 10 (9 rows) SELECT * FROM y; a ---- 11 12 13 14 15 16 17 18 19 20 21 (11 rows) -- forward reference WITH RECURSIVE t AS ( INSERT INTO y SELECT a+5 FROM t2 WHERE a > 5 RETURNING * ), t2 AS ( UPDATE y SET a=a-11 RETURNING * ) SELECT * FROM t UNION ALL SELECT * FROM t2; a ---- 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 (16 rows) SELECT * FROM y; a ---- 0 1 2 3 4 5 6 11 7 12 8 13 9 14 10 15 (16 rows) -- unconditional DO INSTEAD rule CREATE RULE y_rule AS ON DELETE TO y DO INSTEAD INSERT INTO y VALUES(42) RETURNING *; WITH t AS ( DELETE FROM y RETURNING * ) SELECT * FROM t; a ---- 42 (1 row) SELECT * FROM y; a ---- 0 1 2 3 4 5 6 11 7 12 8 13 9 14 10 15 42 (17 rows) DROP RULE y_rule ON y; -- a truly recursive CTE in the same list WITH RECURSIVE t(a) AS ( SELECT 0 UNION ALL SELECT a+1 FROM t WHERE a+1 < 5 ), t2 as ( INSERT INTO y SELECT * FROM t RETURNING * ) SELECT * FROM t2 JOIN y USING (a) ORDER BY a; a --- 0 1 2 3 4 (5 rows) SELECT * FROM y; a ---- 0 1 2 3 4 5 6 11 7 12 8 13 9 14 10 15 42 0 1 2 3 4 (22 rows) -- data-modifying WITH in a modifying statement WITH t AS ( DELETE FROM y WHERE a <= 10 RETURNING * ) INSERT INTO y SELECT -a FROM t RETURNING *; a ----- 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 0 -1 -2 -3 -4 (16 rows) SELECT * FROM y; a ----- 11 12 13 14 15 42 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 0 -1 -2 -3 -4 (22 rows) -- check that WITH query is run to completion even if outer query isn't WITH t AS ( UPDATE y SET a = a * 100 RETURNING * ) SELECT * FROM t LIMIT 10; a ------ 1100 1200 1300 1400 1500 4200 0 -100 -200 -300 (10 rows) SELECT * FROM y; a ------- 1100 1200 1300 1400 1500 4200 0 -100 -200 -300 -400 -500 -600 -700 -800 -900 -1000 0 -100 -200 -300 -400 (22 rows) -- check that run to completion happens in proper ordering TRUNCATE TABLE y; INSERT INTO y SELECT generate_series(1, 3); CREATE TEMPORARY TABLE yy (a INTEGER); WITH RECURSIVE t1 AS ( INSERT INTO y SELECT * FROM y RETURNING * ), t2 AS ( INSERT INTO yy SELECT * FROM t1 RETURNING * ) SELECT 1; ?column? ---------- 1 (1 row) SELECT * FROM y; a --- 1 2 3 1 2 3 (6 rows) SELECT * FROM yy; a --- 1 2 3 (3 rows) WITH RECURSIVE t1 AS ( INSERT INTO yy SELECT * FROM t2 RETURNING * ), t2 AS ( INSERT INTO y SELECT * FROM y RETURNING * ) SELECT 1; ?column? ---------- 1 (1 row) SELECT * FROM y; a --- 1 2 3 1 2 3 1 2 3 1 2 3 (12 rows) SELECT * FROM yy; a --- 1 2 3 1 2 3 1 2 3 (9 rows) -- triggers TRUNCATE TABLE y; INSERT INTO y SELECT generate_series(1, 10); CREATE FUNCTION y_trigger() RETURNS trigger AS $$ begin raise notice 'y_trigger: a = %', new.a; return new; end; $$ LANGUAGE plpgsql; CREATE TRIGGER y_trig BEFORE INSERT ON y FOR EACH ROW EXECUTE PROCEDURE y_trigger(); WITH t AS ( INSERT INTO y VALUES (21), (22), (23) RETURNING * ) SELECT * FROM t; NOTICE: y_trigger: a = 21 NOTICE: y_trigger: a = 22 NOTICE: y_trigger: a = 23 a ---- 21 22 23 (3 rows) SELECT * FROM y; a ---- 1 2 3 4 5 6 7 8 9 10 21 22 23 (13 rows) DROP TRIGGER y_trig ON y; CREATE TRIGGER y_trig AFTER INSERT ON y FOR EACH ROW EXECUTE PROCEDURE y_trigger(); WITH t AS ( INSERT INTO y VALUES (31), (32), (33) RETURNING * ) SELECT * FROM t; NOTICE: y_trigger: a = 31 NOTICE: y_trigger: a = 32 NOTICE: y_trigger: a = 33 a ---- 31 32 33 (3 rows) SELECT * FROM y; a ---- 1 2 3 4 5 6 7 8 9 10 21 22 23 31 32 33 (16 rows) DROP TRIGGER y_trig ON y; CREATE OR REPLACE FUNCTION y_trigger() RETURNS trigger AS $$ begin raise notice 'y_trigger'; return null; end; $$ LANGUAGE plpgsql; CREATE TRIGGER y_trig AFTER INSERT ON y FOR EACH STATEMENT EXECUTE PROCEDURE y_trigger(); WITH t AS ( INSERT INTO y VALUES (41), (42), (43) RETURNING * ) SELECT * FROM t; NOTICE: y_trigger a ---- 41 42 43 (3 rows) SELECT * FROM y; a ---- 1 2 3 4 5 6 7 8 9 10 21 22 23 31 32 33 41 42 43 (19 rows) DROP TRIGGER y_trig ON y; DROP FUNCTION y_trigger(); -- error cases -- data-modifying WITH tries to use its own output WITH RECURSIVE t AS ( INSERT INTO y SELECT * FROM t ) VALUES(FALSE); ERROR: recursive query "t" must not contain data-modifying statements LINE 1: WITH RECURSIVE t AS ( ^ -- no RETURNING in a referenced data-modifying WITH WITH t AS ( INSERT INTO y VALUES(0) ) SELECT * FROM t; ERROR: WITH query "t" does not have a RETURNING clause LINE 4: SELECT * FROM t; ^ -- data-modifying WITH allowed only at the top level SELECT * FROM ( WITH t AS (UPDATE y SET a=a+1 RETURNING *) SELECT * FROM t ) ss; ERROR: WITH clause containing a data-modifying statement must be at the top level LINE 2: WITH t AS (UPDATE y SET a=a+1 RETURNING *) ^ -- most variants of rules aren't allowed CREATE RULE y_rule AS ON INSERT TO y WHERE a=0 DO INSTEAD DELETE FROM y; WITH t AS ( INSERT INTO y VALUES(0) ) VALUES(FALSE); ERROR: conditional DO INSTEAD rules are not supported for data-modifying statements in WITH DROP RULE y_rule ON y;