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163 lines
4.7 KiB
SQL
163 lines
4.7 KiB
SQL
/**
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* Based on https://github.com/postgres/postgres/blob/master/src/test/regress/sql/with.sql, license:
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*
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* PostgreSQL Database Management System
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* (formerly known as Postgres, then as Postgres95)
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*
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* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
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*
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* Portions Copyright (c) 1994, The Regents of the University of California
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*
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* Permission to use, copy, modify, and distribute this software and its
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* documentation for any purpose, without fee, and without a written agreement
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* is hereby granted, provided that the above copyright notice and this
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* paragraph and the following two paragraphs appear in all copies.
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*
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* IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
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* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
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* DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO
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*PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*/
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--
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-- Tests for common table expressions (WITH query, ... SELECT ...)
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--
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-- { echoOn }
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SET allow_experimental_analyzer = 1;
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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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DROP TABLE IF EXISTS department;
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CREATE TABLE department (
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id UInt64, -- department ID
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parent_department UInt64, -- upper department ID
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name String -- department name
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)
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ENGINE=TinyLog;
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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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SELECT name as root_name, * FROM department WHERE name = 'A'
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UNION ALL
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-- recursive term
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SELECT sd.root_name, 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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WITH RECURSIVE subdepartment AS
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(
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-- non recursive term
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SELECT 1 AS level, * 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 AS
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(
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-- non recursive term
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SELECT 1 AS level, * 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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(
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WITH RECURSIVE t AS (
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SELECT toUInt64(1) AS n UNION ALL SELECT n + 1 FROM t WHERE n < 500
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)
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SELECT * FROM t
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) AS t WHERE n < (
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SELECT count(*) FROM (
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WITH RECURSIVE t AS (
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SELECT toUInt64(1) AS n 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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-- 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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-- recursive term has sub-UNION
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WITH RECURSIVE t AS (
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SELECT 1 AS i, 2 AS j
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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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-- { echoOff }
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