mirror of
https://github.com/postgres/postgres.git
synced 2026-06-02 13:58:10 -04:00
Tom Lane
0a7abcd4c9
RecursiveUnion to which it refers. It turns out that we can just postpone the relevant initialization steps until the first exec call for the node, by which time the ancestor node must surely be initialized. Per report from Greg Stark.
430 lines
11 KiB
SQL
430 lines
11 KiB
SQL
--
|
|
-- Tests for common table expressions (WITH query, ... SELECT ...)
|
|
--
|
|
|
|
-- Basic WITH
|
|
WITH q1(x,y) AS (SELECT 1,2)
|
|
SELECT * FROM q1, q1 AS q2;
|
|
|
|
-- 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;
|
|
|
|
-- 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;
|
|
|
|
WITH RECURSIVE t(n) AS (
|
|
SELECT (VALUES(1))
|
|
UNION ALL
|
|
SELECT n+1 FROM t WHERE n < 5
|
|
)
|
|
SELECT * FROM t;
|
|
|
|
-- 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;
|
|
|
|
-- 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;
|
|
|
|
-- UNION case should have same property
|
|
WITH RECURSIVE t(n) AS (
|
|
SELECT 1
|
|
UNION
|
|
SELECT n+1 FROM t)
|
|
SELECT * FROM t LIMIT 10;
|
|
|
|
-- 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;
|
|
|
|
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;
|
|
|
|
--
|
|
-- 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
|
|
);
|
|
|
|
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;
|
|
|
|
-- 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;
|
|
|
|
-- 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;
|
|
|
|
-- "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;
|
|
|
|
-- 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);
|
|
|
|
-- 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);
|
|
|
|
-- 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;
|
|
|
|
-- Check reverse listing
|
|
SELECT pg_get_viewdef('vsubdepartment'::regclass);
|
|
SELECT pg_get_viewdef('vsubdepartment'::regclass, true);
|
|
|
|
-- 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;
|
|
|
|
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;
|
|
|
|
-- 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;
|
|
|
|
--
|
|
-- different tree example
|
|
--
|
|
CREATE TEMPORARY TABLE tree(
|
|
id INTEGER PRIMARY KEY,
|
|
parent_id INTEGER REFERENCES tree(id)
|
|
);
|
|
|
|
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;
|
|
|
|
-- 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;
|
|
|
|
--
|
|
-- 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;
|
|
|
|
-- 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;
|
|
|
|
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);
|
|
|
|
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);
|
|
|
|
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;
|
|
|
|
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;
|
|
|
|
--
|
|
-- error cases
|
|
--
|
|
|
|
-- INTERSECT
|
|
WITH RECURSIVE x(n) AS (SELECT 1 INTERSECT SELECT n+1 FROM x)
|
|
SELECT * FROM x;
|
|
|
|
WITH RECURSIVE x(n) AS (SELECT 1 INTERSECT ALL SELECT n+1 FROM x)
|
|
SELECT * FROM x;
|
|
|
|
-- EXCEPT
|
|
WITH RECURSIVE x(n) AS (SELECT 1 EXCEPT SELECT n+1 FROM x)
|
|
SELECT * FROM x;
|
|
|
|
WITH RECURSIVE x(n) AS (SELECT 1 EXCEPT ALL SELECT n+1 FROM x)
|
|
SELECT * FROM x;
|
|
|
|
-- no non-recursive term
|
|
WITH RECURSIVE x(n) AS (SELECT n FROM x)
|
|
SELECT * 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;
|
|
|
|
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;
|
|
|
|
-- 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;
|
|
|
|
-- 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;
|
|
|
|
-- subquery
|
|
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x
|
|
WHERE n IN (SELECT * FROM x))
|
|
SELECT * FROM x;
|
|
|
|
-- aggregate functions
|
|
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT count(*) FROM x)
|
|
SELECT * FROM x;
|
|
|
|
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT sum(n) FROM x)
|
|
SELECT * FROM x;
|
|
|
|
-- ORDER BY
|
|
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x ORDER BY 1)
|
|
SELECT * FROM x;
|
|
|
|
-- LIMIT/OFFSET
|
|
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x LIMIT 10 OFFSET 1)
|
|
SELECT * FROM x;
|
|
|
|
-- FOR UPDATE
|
|
WITH RECURSIVE x(n) AS (SELECT 1 UNION ALL SELECT n+1 FROM x FOR UPDATE)
|
|
SELECT * FROM x;
|
|
|
|
-- 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;
|
|
|
|
-- 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;
|
|
|
|
-- 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;
|
|
|
|
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;
|
|
|
|
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;
|
|
|
|
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;
|
|
|
|
-- 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;
|