2000-01-06 07:40:54 +01:00
|
|
|
--
|
2000-10-05 21:11:39 +02:00
|
|
|
-- UNION (also INTERSECT, EXCEPT)
|
2000-01-06 07:40:54 +01:00
|
|
|
--
|
|
|
|
-- Simple UNION constructs
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1 AS two UNION SELECT 2 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
two
|
|
|
|
-----
|
|
|
|
1
|
|
|
|
2
|
1998-05-29 15:22:42 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1 AS one UNION SELECT 1 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
one
|
|
|
|
-----
|
|
|
|
1
|
1998-05-29 15:22:42 +02:00
|
|
|
(1 row)
|
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
SELECT 1 AS two UNION ALL SELECT 2;
|
|
|
|
two
|
|
|
|
-----
|
|
|
|
1
|
|
|
|
2
|
1998-05-29 15:22:42 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
SELECT 1 AS two UNION ALL SELECT 1;
|
|
|
|
two
|
|
|
|
-----
|
|
|
|
1
|
|
|
|
1
|
1998-05-29 15:22:42 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1 AS three UNION SELECT 2 UNION SELECT 3 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
three
|
|
|
|
-------
|
|
|
|
1
|
|
|
|
2
|
|
|
|
3
|
1998-05-29 15:22:42 +02:00
|
|
|
(3 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1 AS two UNION SELECT 2 UNION SELECT 2 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
two
|
|
|
|
-----
|
|
|
|
1
|
|
|
|
2
|
1998-05-29 15:22:42 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1 AS three UNION SELECT 2 UNION ALL SELECT 2 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
three
|
|
|
|
-------
|
|
|
|
1
|
|
|
|
2
|
|
|
|
2
|
1998-05-29 15:22:42 +02:00
|
|
|
(3 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1.1 AS two UNION SELECT 2.2 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
two
|
|
|
|
-----
|
|
|
|
1.1
|
|
|
|
2.2
|
1998-05-29 15:22:42 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
-- Mixed types
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1.1 AS two UNION SELECT 2 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
two
|
|
|
|
-----
|
|
|
|
1.1
|
|
|
|
2
|
1998-05-29 15:22:42 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1 AS two UNION SELECT 2.2 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
two
|
|
|
|
-----
|
|
|
|
1
|
2000-10-05 21:11:39 +02:00
|
|
|
2.2
|
1998-05-29 15:22:42 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1 AS one UNION SELECT 1.0::float8 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
one
|
|
|
|
-----
|
|
|
|
1
|
1998-05-29 15:22:42 +02:00
|
|
|
(1 row)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1.1 AS two UNION ALL SELECT 2 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
two
|
|
|
|
-----
|
|
|
|
1.1
|
|
|
|
2
|
1998-05-29 15:22:42 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1.0::float8 AS two UNION ALL SELECT 1 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
two
|
|
|
|
-----
|
2003-11-02 23:35:26 +01:00
|
|
|
1
|
2000-01-06 07:40:54 +01:00
|
|
|
1
|
1998-05-29 15:22:42 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1.1 AS three UNION SELECT 2 UNION SELECT 3 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
three
|
|
|
|
-------
|
2000-10-05 21:11:39 +02:00
|
|
|
1.1
|
2000-01-06 07:40:54 +01:00
|
|
|
2
|
|
|
|
3
|
1998-05-29 15:22:42 +02:00
|
|
|
(3 rows)
|
|
|
|
|
2008-08-07 03:11:52 +02:00
|
|
|
SELECT 1.1::float8 AS two UNION SELECT 2 UNION SELECT 2.0::float8 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
two
|
|
|
|
-----
|
2000-10-05 21:11:39 +02:00
|
|
|
1.1
|
2000-01-06 07:40:54 +01:00
|
|
|
2
|
1998-05-29 15:22:42 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1.1 AS three UNION SELECT 2 UNION ALL SELECT 2 ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
three
|
|
|
|
-------
|
2000-10-05 21:11:39 +02:00
|
|
|
1.1
|
2000-01-06 07:40:54 +01:00
|
|
|
2
|
|
|
|
2
|
1998-05-29 15:22:42 +02:00
|
|
|
(3 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT 1.1 AS two UNION (SELECT 2 UNION ALL SELECT 2) ORDER BY 1;
|
2000-10-05 21:11:39 +02:00
|
|
|
two
|
|
|
|
-----
|
|
|
|
1.1
|
|
|
|
2
|
|
|
|
(2 rows)
|
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
--
|
|
|
|
-- Try testing from tables...
|
|
|
|
--
|
|
|
|
SELECT f1 AS five FROM FLOAT8_TBL
|
1998-05-29 15:22:42 +02:00
|
|
|
UNION
|
2008-08-07 03:11:52 +02:00
|
|
|
SELECT f1 FROM FLOAT8_TBL
|
|
|
|
ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
five
|
|
|
|
-----------------------
|
|
|
|
-1.2345678901234e+200
|
|
|
|
-1004.3
|
|
|
|
-34.84
|
|
|
|
-1.2345678901234e-200
|
|
|
|
0
|
1998-05-29 15:22:42 +02:00
|
|
|
(5 rows)
|
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
SELECT f1 AS ten FROM FLOAT8_TBL
|
1998-05-29 15:22:42 +02:00
|
|
|
UNION ALL
|
|
|
|
SELECT f1 FROM FLOAT8_TBL;
|
2000-01-06 07:40:54 +01:00
|
|
|
ten
|
|
|
|
-----------------------
|
|
|
|
0
|
|
|
|
-34.84
|
|
|
|
-1004.3
|
|
|
|
-1.2345678901234e+200
|
|
|
|
-1.2345678901234e-200
|
|
|
|
0
|
|
|
|
-34.84
|
|
|
|
-1004.3
|
|
|
|
-1.2345678901234e+200
|
|
|
|
-1.2345678901234e-200
|
1998-05-29 15:22:42 +02:00
|
|
|
(10 rows)
|
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
SELECT f1 AS nine FROM FLOAT8_TBL
|
1998-05-29 15:22:42 +02:00
|
|
|
UNION
|
2008-08-07 03:11:52 +02:00
|
|
|
SELECT f1 FROM INT4_TBL
|
|
|
|
ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
nine
|
|
|
|
-----------------------
|
|
|
|
-1.2345678901234e+200
|
|
|
|
-2147483647
|
|
|
|
-123456
|
|
|
|
-1004.3
|
|
|
|
-34.84
|
|
|
|
-1.2345678901234e-200
|
|
|
|
0
|
|
|
|
123456
|
|
|
|
2147483647
|
1998-05-29 15:22:42 +02:00
|
|
|
(9 rows)
|
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
SELECT f1 AS ten FROM FLOAT8_TBL
|
1998-05-29 15:22:42 +02:00
|
|
|
UNION ALL
|
|
|
|
SELECT f1 FROM INT4_TBL;
|
2000-01-06 07:40:54 +01:00
|
|
|
ten
|
|
|
|
-----------------------
|
|
|
|
0
|
|
|
|
-34.84
|
|
|
|
-1004.3
|
|
|
|
-1.2345678901234e+200
|
|
|
|
-1.2345678901234e-200
|
|
|
|
0
|
|
|
|
123456
|
|
|
|
-123456
|
|
|
|
2147483647
|
|
|
|
-2147483647
|
1998-05-29 15:22:42 +02:00
|
|
|
(10 rows)
|
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
SELECT f1 AS five FROM FLOAT8_TBL
|
1998-05-29 15:22:42 +02:00
|
|
|
WHERE f1 BETWEEN -1e6 AND 1e6
|
|
|
|
UNION
|
|
|
|
SELECT f1 FROM INT4_TBL
|
2016-10-10 22:41:57 +02:00
|
|
|
WHERE f1 BETWEEN 0 AND 1000000
|
|
|
|
ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
five
|
|
|
|
-----------------------
|
|
|
|
-1004.3
|
|
|
|
-34.84
|
|
|
|
-1.2345678901234e-200
|
|
|
|
0
|
|
|
|
123456
|
1998-05-29 15:22:42 +02:00
|
|
|
(5 rows)
|
|
|
|
|
2003-05-26 02:11:29 +02:00
|
|
|
SELECT CAST(f1 AS char(4)) AS three FROM VARCHAR_TBL
|
1998-05-29 15:22:42 +02:00
|
|
|
UNION
|
2008-08-07 03:11:52 +02:00
|
|
|
SELECT f1 FROM CHAR_TBL
|
|
|
|
ORDER BY 1;
|
2003-05-26 02:11:29 +02:00
|
|
|
three
|
|
|
|
-------
|
2000-01-06 07:40:54 +01:00
|
|
|
a
|
|
|
|
ab
|
|
|
|
abcd
|
2003-05-26 02:11:29 +02:00
|
|
|
(3 rows)
|
1998-05-29 15:22:42 +02:00
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
SELECT f1 AS three FROM VARCHAR_TBL
|
1998-05-29 15:22:42 +02:00
|
|
|
UNION
|
2008-08-07 03:11:52 +02:00
|
|
|
SELECT CAST(f1 AS varchar) FROM CHAR_TBL
|
|
|
|
ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
three
|
|
|
|
-------
|
|
|
|
a
|
|
|
|
ab
|
|
|
|
abcd
|
1998-05-29 15:22:42 +02:00
|
|
|
(3 rows)
|
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
SELECT f1 AS eight FROM VARCHAR_TBL
|
1998-05-29 15:22:42 +02:00
|
|
|
UNION ALL
|
|
|
|
SELECT f1 FROM CHAR_TBL;
|
2000-01-06 07:40:54 +01:00
|
|
|
eight
|
|
|
|
-------
|
|
|
|
a
|
|
|
|
ab
|
|
|
|
abcd
|
|
|
|
abcd
|
2003-05-26 02:11:29 +02:00
|
|
|
a
|
|
|
|
ab
|
2000-01-06 07:40:54 +01:00
|
|
|
abcd
|
|
|
|
abcd
|
1998-05-29 15:22:42 +02:00
|
|
|
(8 rows)
|
|
|
|
|
2000-01-06 07:40:54 +01:00
|
|
|
SELECT f1 AS five FROM TEXT_TBL
|
1998-05-29 15:22:42 +02:00
|
|
|
UNION
|
|
|
|
SELECT f1 FROM VARCHAR_TBL
|
|
|
|
UNION
|
2008-08-07 03:11:52 +02:00
|
|
|
SELECT TRIM(TRAILING FROM f1) FROM CHAR_TBL
|
|
|
|
ORDER BY 1;
|
2000-01-06 07:40:54 +01:00
|
|
|
five
|
|
|
|
-------------------
|
|
|
|
a
|
|
|
|
ab
|
|
|
|
abcd
|
|
|
|
doh!
|
|
|
|
hi de ho neighbor
|
1998-05-29 15:22:42 +02:00
|
|
|
(5 rows)
|
|
|
|
|
2000-10-05 21:11:39 +02:00
|
|
|
--
|
|
|
|
-- INTERSECT and EXCEPT
|
|
|
|
--
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT q2 FROM int8_tbl INTERSECT SELECT q1 FROM int8_tbl ORDER BY 1;
|
2000-10-05 21:11:39 +02:00
|
|
|
q2
|
|
|
|
------------------
|
2009-02-09 22:18:28 +01:00
|
|
|
123
|
2016-10-10 22:41:57 +02:00
|
|
|
4567890123456789
|
2000-10-05 21:11:39 +02:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT q2 FROM int8_tbl INTERSECT ALL SELECT q1 FROM int8_tbl ORDER BY 1;
|
2000-10-05 21:11:39 +02:00
|
|
|
q2
|
|
|
|
------------------
|
2016-10-10 22:41:57 +02:00
|
|
|
123
|
2000-10-05 21:11:39 +02:00
|
|
|
4567890123456789
|
|
|
|
4567890123456789
|
|
|
|
(3 rows)
|
|
|
|
|
2008-08-07 05:04:04 +02:00
|
|
|
SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl ORDER BY 1;
|
2000-10-05 21:11:39 +02:00
|
|
|
q2
|
|
|
|
-------------------
|
|
|
|
-4567890123456789
|
|
|
|
456
|
|
|
|
(2 rows)
|
|
|
|
|
2008-08-07 05:04:04 +02:00
|
|
|
SELECT q2 FROM int8_tbl EXCEPT ALL SELECT q1 FROM int8_tbl ORDER BY 1;
|
2000-10-05 21:11:39 +02:00
|
|
|
q2
|
|
|
|
-------------------
|
|
|
|
-4567890123456789
|
|
|
|
456
|
|
|
|
(2 rows)
|
|
|
|
|
2008-08-07 05:04:04 +02:00
|
|
|
SELECT q2 FROM int8_tbl EXCEPT ALL SELECT DISTINCT q1 FROM int8_tbl ORDER BY 1;
|
2000-10-05 21:11:39 +02:00
|
|
|
q2
|
|
|
|
-------------------
|
|
|
|
-4567890123456789
|
|
|
|
456
|
|
|
|
4567890123456789
|
|
|
|
(3 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT q1 FROM int8_tbl EXCEPT SELECT q2 FROM int8_tbl ORDER BY 1;
|
2000-11-09 03:47:49 +01:00
|
|
|
q1
|
|
|
|
----
|
|
|
|
(0 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT q1 FROM int8_tbl EXCEPT ALL SELECT q2 FROM int8_tbl ORDER BY 1;
|
2000-11-09 03:47:49 +01:00
|
|
|
q1
|
|
|
|
------------------
|
2009-02-09 22:18:28 +01:00
|
|
|
123
|
2016-10-10 22:41:57 +02:00
|
|
|
4567890123456789
|
2000-11-09 03:47:49 +01:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT q1 FROM int8_tbl EXCEPT ALL SELECT DISTINCT q2 FROM int8_tbl ORDER BY 1;
|
2000-11-09 03:47:49 +01:00
|
|
|
q1
|
|
|
|
------------------
|
2016-10-10 22:41:57 +02:00
|
|
|
123
|
2000-11-09 03:47:49 +01:00
|
|
|
4567890123456789
|
|
|
|
4567890123456789
|
|
|
|
(3 rows)
|
|
|
|
|
2013-08-02 18:49:03 +02:00
|
|
|
SELECT q1 FROM int8_tbl EXCEPT ALL SELECT q1 FROM int8_tbl FOR NO KEY UPDATE;
|
|
|
|
ERROR: FOR NO KEY UPDATE is not allowed with UNION/INTERSECT/EXCEPT
|
2017-04-07 18:18:38 +02:00
|
|
|
-- nested cases
|
|
|
|
(SELECT 1,2,3 UNION SELECT 4,5,6) INTERSECT SELECT 4,5,6;
|
|
|
|
?column? | ?column? | ?column?
|
|
|
|
----------+----------+----------
|
|
|
|
4 | 5 | 6
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
(SELECT 1,2,3 UNION SELECT 4,5,6 ORDER BY 1,2) INTERSECT SELECT 4,5,6;
|
|
|
|
?column? | ?column? | ?column?
|
|
|
|
----------+----------+----------
|
|
|
|
4 | 5 | 6
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
(SELECT 1,2,3 UNION SELECT 4,5,6) EXCEPT SELECT 4,5,6;
|
|
|
|
?column? | ?column? | ?column?
|
|
|
|
----------+----------+----------
|
|
|
|
1 | 2 | 3
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
(SELECT 1,2,3 UNION SELECT 4,5,6 ORDER BY 1,2) EXCEPT SELECT 4,5,6;
|
|
|
|
?column? | ?column? | ?column?
|
|
|
|
----------+----------+----------
|
|
|
|
1 | 2 | 3
|
|
|
|
(1 row)
|
|
|
|
|
2017-08-11 22:52:12 +02:00
|
|
|
-- exercise both hashed and sorted implementations of INTERSECT/EXCEPT
|
|
|
|
set enable_hashagg to on;
|
|
|
|
explain (costs off)
|
|
|
|
select count(*) from
|
|
|
|
( select unique1 from tenk1 intersect select fivethous from tenk1 ) ss;
|
|
|
|
QUERY PLAN
|
|
|
|
------------------------------------------------------------------------------------
|
|
|
|
Aggregate
|
|
|
|
-> Subquery Scan on ss
|
|
|
|
-> HashSetOp Intersect
|
|
|
|
-> Append
|
|
|
|
-> Subquery Scan on "*SELECT* 2"
|
|
|
|
-> Seq Scan on tenk1
|
|
|
|
-> Subquery Scan on "*SELECT* 1"
|
|
|
|
-> Index Only Scan using tenk1_unique1 on tenk1 tenk1_1
|
|
|
|
(8 rows)
|
|
|
|
|
|
|
|
select count(*) from
|
|
|
|
( select unique1 from tenk1 intersect select fivethous from tenk1 ) ss;
|
|
|
|
count
|
|
|
|
-------
|
|
|
|
5000
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
explain (costs off)
|
|
|
|
select unique1 from tenk1 except select unique2 from tenk1 where unique2 != 10;
|
|
|
|
QUERY PLAN
|
|
|
|
------------------------------------------------------------------------
|
|
|
|
HashSetOp Except
|
|
|
|
-> Append
|
|
|
|
-> Subquery Scan on "*SELECT* 1"
|
|
|
|
-> Index Only Scan using tenk1_unique1 on tenk1
|
|
|
|
-> Subquery Scan on "*SELECT* 2"
|
|
|
|
-> Index Only Scan using tenk1_unique2 on tenk1 tenk1_1
|
|
|
|
Filter: (unique2 <> 10)
|
|
|
|
(7 rows)
|
|
|
|
|
|
|
|
select unique1 from tenk1 except select unique2 from tenk1 where unique2 != 10;
|
|
|
|
unique1
|
|
|
|
---------
|
|
|
|
10
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
set enable_hashagg to off;
|
|
|
|
explain (costs off)
|
|
|
|
select count(*) from
|
|
|
|
( select unique1 from tenk1 intersect select fivethous from tenk1 ) ss;
|
|
|
|
QUERY PLAN
|
|
|
|
------------------------------------------------------------------------------------------
|
|
|
|
Aggregate
|
|
|
|
-> Subquery Scan on ss
|
|
|
|
-> SetOp Intersect
|
|
|
|
-> Sort
|
|
|
|
Sort Key: "*SELECT* 2".fivethous
|
|
|
|
-> Append
|
|
|
|
-> Subquery Scan on "*SELECT* 2"
|
|
|
|
-> Seq Scan on tenk1
|
|
|
|
-> Subquery Scan on "*SELECT* 1"
|
|
|
|
-> Index Only Scan using tenk1_unique1 on tenk1 tenk1_1
|
|
|
|
(10 rows)
|
|
|
|
|
|
|
|
select count(*) from
|
|
|
|
( select unique1 from tenk1 intersect select fivethous from tenk1 ) ss;
|
|
|
|
count
|
|
|
|
-------
|
|
|
|
5000
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
explain (costs off)
|
|
|
|
select unique1 from tenk1 except select unique2 from tenk1 where unique2 != 10;
|
|
|
|
QUERY PLAN
|
|
|
|
------------------------------------------------------------------------------
|
|
|
|
SetOp Except
|
|
|
|
-> Sort
|
|
|
|
Sort Key: "*SELECT* 1".unique1
|
|
|
|
-> Append
|
|
|
|
-> Subquery Scan on "*SELECT* 1"
|
|
|
|
-> Index Only Scan using tenk1_unique1 on tenk1
|
|
|
|
-> Subquery Scan on "*SELECT* 2"
|
|
|
|
-> Index Only Scan using tenk1_unique2 on tenk1 tenk1_1
|
|
|
|
Filter: (unique2 <> 10)
|
|
|
|
(9 rows)
|
|
|
|
|
|
|
|
select unique1 from tenk1 except select unique2 from tenk1 where unique2 != 10;
|
|
|
|
unique1
|
|
|
|
---------
|
|
|
|
10
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
reset enable_hashagg;
|
2000-10-05 21:11:39 +02:00
|
|
|
--
|
|
|
|
-- Mixed types
|
|
|
|
--
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT f1 FROM float8_tbl INTERSECT SELECT f1 FROM int4_tbl ORDER BY 1;
|
2000-10-05 21:11:39 +02:00
|
|
|
f1
|
|
|
|
----
|
|
|
|
0
|
|
|
|
(1 row)
|
|
|
|
|
2008-08-07 05:04:04 +02:00
|
|
|
SELECT f1 FROM float8_tbl EXCEPT SELECT f1 FROM int4_tbl ORDER BY 1;
|
2000-10-05 21:11:39 +02:00
|
|
|
f1
|
|
|
|
-----------------------
|
|
|
|
-1.2345678901234e+200
|
|
|
|
-1004.3
|
|
|
|
-34.84
|
|
|
|
-1.2345678901234e-200
|
|
|
|
(4 rows)
|
|
|
|
|
2000-11-09 03:47:49 +01:00
|
|
|
--
|
|
|
|
-- Operator precedence and (((((extra))))) parentheses
|
|
|
|
--
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT q1 FROM int8_tbl INTERSECT SELECT q2 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl ORDER BY 1;
|
2000-11-09 03:47:49 +01:00
|
|
|
q1
|
|
|
|
-------------------
|
2016-10-10 22:41:57 +02:00
|
|
|
-4567890123456789
|
|
|
|
123
|
2009-02-09 22:18:28 +01:00
|
|
|
123
|
2000-11-09 03:47:49 +01:00
|
|
|
456
|
|
|
|
4567890123456789
|
|
|
|
4567890123456789
|
2016-10-10 22:41:57 +02:00
|
|
|
4567890123456789
|
2000-11-09 03:47:49 +01:00
|
|
|
(7 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT q1 FROM int8_tbl INTERSECT (((SELECT q2 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl))) ORDER BY 1;
|
2000-11-09 03:47:49 +01:00
|
|
|
q1
|
|
|
|
------------------
|
2009-02-09 22:18:28 +01:00
|
|
|
123
|
2016-10-10 22:41:57 +02:00
|
|
|
4567890123456789
|
2000-11-09 03:47:49 +01:00
|
|
|
(2 rows)
|
|
|
|
|
2016-10-10 22:41:57 +02:00
|
|
|
(((SELECT q1 FROM int8_tbl INTERSECT SELECT q2 FROM int8_tbl ORDER BY 1))) UNION ALL SELECT q2 FROM int8_tbl;
|
2000-11-09 03:47:49 +01:00
|
|
|
q1
|
|
|
|
-------------------
|
2009-02-09 22:18:28 +01:00
|
|
|
123
|
2016-10-10 22:41:57 +02:00
|
|
|
4567890123456789
|
2000-11-09 03:47:49 +01:00
|
|
|
456
|
|
|
|
4567890123456789
|
|
|
|
123
|
|
|
|
4567890123456789
|
|
|
|
-4567890123456789
|
|
|
|
(7 rows)
|
|
|
|
|
2008-08-07 05:04:04 +02:00
|
|
|
SELECT q1 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl ORDER BY 1;
|
2000-11-09 03:47:49 +01:00
|
|
|
q1
|
|
|
|
-------------------
|
|
|
|
-4567890123456789
|
|
|
|
456
|
|
|
|
(2 rows)
|
|
|
|
|
2008-08-07 05:04:04 +02:00
|
|
|
SELECT q1 FROM int8_tbl UNION ALL (((SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl ORDER BY 1)));
|
2000-11-09 03:47:49 +01:00
|
|
|
q1
|
|
|
|
-------------------
|
|
|
|
123
|
|
|
|
123
|
|
|
|
4567890123456789
|
|
|
|
4567890123456789
|
|
|
|
4567890123456789
|
|
|
|
-4567890123456789
|
|
|
|
456
|
|
|
|
(7 rows)
|
|
|
|
|
2008-08-07 05:04:04 +02:00
|
|
|
(((SELECT q1 FROM int8_tbl UNION ALL SELECT q2 FROM int8_tbl))) EXCEPT SELECT q1 FROM int8_tbl ORDER BY 1;
|
2000-11-09 03:47:49 +01:00
|
|
|
q1
|
|
|
|
-------------------
|
|
|
|
-4567890123456789
|
|
|
|
456
|
|
|
|
(2 rows)
|
|
|
|
|
|
|
|
--
|
|
|
|
-- Subqueries with ORDER BY & LIMIT clauses
|
|
|
|
--
|
|
|
|
-- In this syntax, ORDER BY/LIMIT apply to the result of the EXCEPT
|
|
|
|
SELECT q1,q2 FROM int8_tbl EXCEPT SELECT q2,q1 FROM int8_tbl
|
|
|
|
ORDER BY q2,q1;
|
|
|
|
q1 | q2
|
|
|
|
------------------+-------------------
|
|
|
|
4567890123456789 | -4567890123456789
|
|
|
|
123 | 456
|
|
|
|
(2 rows)
|
|
|
|
|
|
|
|
-- This should fail, because q2 isn't a name of an EXCEPT output column
|
|
|
|
SELECT q1 FROM int8_tbl EXCEPT SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1;
|
2003-09-25 08:58:07 +02:00
|
|
|
ERROR: column "q2" does not exist
|
2006-03-14 23:48:25 +01:00
|
|
|
LINE 1: ... int8_tbl EXCEPT SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1...
|
|
|
|
^
|
2012-08-08 01:02:54 +02:00
|
|
|
HINT: There is a column named "q2" in table "*SELECT* 2", but it cannot be referenced from this part of the query.
|
2000-11-09 03:47:49 +01:00
|
|
|
-- But this should work:
|
2016-10-10 22:41:57 +02:00
|
|
|
SELECT q1 FROM int8_tbl EXCEPT (((SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1))) ORDER BY 1;
|
2000-11-09 03:47:49 +01:00
|
|
|
q1
|
|
|
|
------------------
|
2009-02-09 22:18:28 +01:00
|
|
|
123
|
2016-10-10 22:41:57 +02:00
|
|
|
4567890123456789
|
2000-11-09 03:47:49 +01:00
|
|
|
(2 rows)
|
|
|
|
|
|
|
|
--
|
|
|
|
-- New syntaxes (7.1) permit new tests
|
|
|
|
--
|
|
|
|
(((((select * from int8_tbl)))));
|
|
|
|
q1 | q2
|
|
|
|
------------------+-------------------
|
|
|
|
123 | 456
|
|
|
|
123 | 4567890123456789
|
|
|
|
4567890123456789 | 123
|
|
|
|
4567890123456789 | 4567890123456789
|
|
|
|
4567890123456789 | -4567890123456789
|
|
|
|
(5 rows)
|
|
|
|
|
2017-12-22 18:08:06 +01:00
|
|
|
--
|
|
|
|
-- Check behavior with empty select list (allowed since 9.4)
|
|
|
|
--
|
|
|
|
select union select;
|
|
|
|
--
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
select intersect select;
|
|
|
|
--
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
select except select;
|
|
|
|
--
|
|
|
|
(0 rows)
|
|
|
|
|
|
|
|
-- check hashed implementation
|
|
|
|
set enable_hashagg = true;
|
|
|
|
set enable_sort = false;
|
|
|
|
explain (costs off)
|
|
|
|
select from generate_series(1,5) union select from generate_series(1,3);
|
|
|
|
QUERY PLAN
|
|
|
|
----------------------------------------------------------------
|
|
|
|
HashAggregate
|
|
|
|
-> Append
|
|
|
|
-> Function Scan on generate_series
|
|
|
|
-> Function Scan on generate_series generate_series_1
|
|
|
|
(4 rows)
|
|
|
|
|
|
|
|
explain (costs off)
|
|
|
|
select from generate_series(1,5) intersect select from generate_series(1,3);
|
|
|
|
QUERY PLAN
|
|
|
|
----------------------------------------------------------------------
|
|
|
|
HashSetOp Intersect
|
|
|
|
-> Append
|
|
|
|
-> Subquery Scan on "*SELECT* 1"
|
|
|
|
-> Function Scan on generate_series
|
|
|
|
-> Subquery Scan on "*SELECT* 2"
|
|
|
|
-> Function Scan on generate_series generate_series_1
|
|
|
|
(6 rows)
|
|
|
|
|
|
|
|
select from generate_series(1,5) union select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
select from generate_series(1,5) union all select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(8 rows)
|
|
|
|
|
|
|
|
select from generate_series(1,5) intersect select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
select from generate_series(1,5) intersect all select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(3 rows)
|
|
|
|
|
|
|
|
select from generate_series(1,5) except select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(0 rows)
|
|
|
|
|
|
|
|
select from generate_series(1,5) except all select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(2 rows)
|
|
|
|
|
|
|
|
-- check sorted implementation
|
|
|
|
set enable_hashagg = false;
|
|
|
|
set enable_sort = true;
|
|
|
|
explain (costs off)
|
|
|
|
select from generate_series(1,5) union select from generate_series(1,3);
|
|
|
|
QUERY PLAN
|
|
|
|
----------------------------------------------------------------
|
|
|
|
Unique
|
|
|
|
-> Append
|
|
|
|
-> Function Scan on generate_series
|
|
|
|
-> Function Scan on generate_series generate_series_1
|
|
|
|
(4 rows)
|
|
|
|
|
|
|
|
explain (costs off)
|
|
|
|
select from generate_series(1,5) intersect select from generate_series(1,3);
|
|
|
|
QUERY PLAN
|
|
|
|
----------------------------------------------------------------------
|
|
|
|
SetOp Intersect
|
|
|
|
-> Append
|
|
|
|
-> Subquery Scan on "*SELECT* 1"
|
|
|
|
-> Function Scan on generate_series
|
|
|
|
-> Subquery Scan on "*SELECT* 2"
|
|
|
|
-> Function Scan on generate_series generate_series_1
|
|
|
|
(6 rows)
|
|
|
|
|
|
|
|
select from generate_series(1,5) union select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
select from generate_series(1,5) union all select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(8 rows)
|
|
|
|
|
|
|
|
select from generate_series(1,5) intersect select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
select from generate_series(1,5) intersect all select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(3 rows)
|
|
|
|
|
|
|
|
select from generate_series(1,5) except select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(0 rows)
|
|
|
|
|
|
|
|
select from generate_series(1,5) except all select from generate_series(1,3);
|
|
|
|
--
|
|
|
|
(2 rows)
|
|
|
|
|
|
|
|
reset enable_hashagg;
|
|
|
|
reset enable_sort;
|
2009-12-16 23:24:13 +01:00
|
|
|
--
|
|
|
|
-- Check handling of a case with unknown constants. We don't guarantee
|
|
|
|
-- an undecorated constant will work in all cases, but historically this
|
|
|
|
-- usage has worked, so test we don't break it.
|
|
|
|
--
|
|
|
|
SELECT a.f1 FROM (SELECT 'test' AS f1 FROM varchar_tbl) a
|
|
|
|
UNION
|
|
|
|
SELECT b.f1 FROM (SELECT f1 FROM varchar_tbl) b
|
|
|
|
ORDER BY 1;
|
|
|
|
f1
|
|
|
|
------
|
|
|
|
a
|
|
|
|
ab
|
|
|
|
abcd
|
|
|
|
test
|
|
|
|
(4 rows)
|
|
|
|
|
|
|
|
-- This should fail, but it should produce an error cursor
|
|
|
|
SELECT '3.4'::numeric UNION SELECT 'foo';
|
|
|
|
ERROR: invalid input syntax for type numeric: "foo"
|
|
|
|
LINE 1: SELECT '3.4'::numeric UNION SELECT 'foo';
|
|
|
|
^
|
2012-01-29 22:31:23 +01:00
|
|
|
--
|
|
|
|
-- Test that expression-index constraints can be pushed down through
|
|
|
|
-- UNION or UNION ALL
|
|
|
|
--
|
|
|
|
CREATE TEMP TABLE t1 (a text, b text);
|
|
|
|
CREATE INDEX t1_ab_idx on t1 ((a || b));
|
|
|
|
CREATE TEMP TABLE t2 (ab text primary key);
|
|
|
|
INSERT INTO t1 VALUES ('a', 'b'), ('x', 'y');
|
|
|
|
INSERT INTO t2 VALUES ('ab'), ('xy');
|
|
|
|
set enable_seqscan = off;
|
|
|
|
set enable_indexscan = on;
|
|
|
|
set enable_bitmapscan = off;
|
|
|
|
explain (costs off)
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT a || b AS ab FROM t1
|
|
|
|
UNION ALL
|
|
|
|
SELECT * FROM t2) t
|
|
|
|
WHERE ab = 'ab';
|
2013-03-14 18:42:51 +01:00
|
|
|
QUERY PLAN
|
|
|
|
---------------------------------------------
|
|
|
|
Append
|
|
|
|
-> Index Scan using t1_ab_idx on t1
|
|
|
|
Index Cond: ((a || b) = 'ab'::text)
|
|
|
|
-> Index Only Scan using t2_pkey on t2
|
|
|
|
Index Cond: (ab = 'ab'::text)
|
|
|
|
(5 rows)
|
2012-01-29 22:31:23 +01:00
|
|
|
|
|
|
|
explain (costs off)
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT a || b AS ab FROM t1
|
|
|
|
UNION
|
|
|
|
SELECT * FROM t2) t
|
|
|
|
WHERE ab = 'ab';
|
|
|
|
QUERY PLAN
|
|
|
|
---------------------------------------------------
|
|
|
|
HashAggregate
|
2013-12-12 17:24:38 +01:00
|
|
|
Group Key: ((t1.a || t1.b))
|
2012-01-29 22:31:23 +01:00
|
|
|
-> Append
|
|
|
|
-> Index Scan using t1_ab_idx on t1
|
|
|
|
Index Cond: ((a || b) = 'ab'::text)
|
|
|
|
-> Index Only Scan using t2_pkey on t2
|
|
|
|
Index Cond: (ab = 'ab'::text)
|
2013-12-12 17:24:38 +01:00
|
|
|
(7 rows)
|
2012-01-29 22:31:23 +01:00
|
|
|
|
2014-03-28 16:50:01 +01:00
|
|
|
--
|
|
|
|
-- Test that ORDER BY for UNION ALL can be pushed down to inheritance
|
|
|
|
-- children.
|
|
|
|
--
|
|
|
|
CREATE TEMP TABLE t1c (b text, a text);
|
|
|
|
ALTER TABLE t1c INHERIT t1;
|
|
|
|
CREATE TEMP TABLE t2c (primary key (ab)) INHERITS (t2);
|
|
|
|
INSERT INTO t1c VALUES ('v', 'w'), ('c', 'd'), ('m', 'n'), ('e', 'f');
|
|
|
|
INSERT INTO t2c VALUES ('vw'), ('cd'), ('mn'), ('ef');
|
|
|
|
CREATE INDEX t1c_ab_idx on t1c ((a || b));
|
|
|
|
set enable_seqscan = on;
|
|
|
|
set enable_indexonlyscan = off;
|
|
|
|
explain (costs off)
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT a || b AS ab FROM t1
|
|
|
|
UNION ALL
|
|
|
|
SELECT ab FROM t2) t
|
|
|
|
ORDER BY 1 LIMIT 8;
|
|
|
|
QUERY PLAN
|
|
|
|
------------------------------------------------
|
|
|
|
Limit
|
|
|
|
-> Merge Append
|
|
|
|
Sort Key: ((t1.a || t1.b))
|
|
|
|
-> Index Scan using t1_ab_idx on t1
|
|
|
|
-> Index Scan using t1c_ab_idx on t1c
|
|
|
|
-> Index Scan using t2_pkey on t2
|
|
|
|
-> Index Scan using t2c_pkey on t2c
|
|
|
|
(7 rows)
|
|
|
|
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT a || b AS ab FROM t1
|
|
|
|
UNION ALL
|
|
|
|
SELECT ab FROM t2) t
|
|
|
|
ORDER BY 1 LIMIT 8;
|
|
|
|
ab
|
|
|
|
----
|
|
|
|
ab
|
|
|
|
ab
|
|
|
|
cd
|
|
|
|
dc
|
|
|
|
ef
|
|
|
|
fe
|
|
|
|
mn
|
|
|
|
nm
|
|
|
|
(8 rows)
|
|
|
|
|
2012-01-29 22:31:23 +01:00
|
|
|
reset enable_seqscan;
|
|
|
|
reset enable_indexscan;
|
|
|
|
reset enable_bitmapscan;
|
2014-06-26 19:40:50 +02:00
|
|
|
-- This simpler variant of the above test has been observed to fail differently
|
|
|
|
create table events (event_id int primary key);
|
|
|
|
create table other_events (event_id int primary key);
|
|
|
|
create table events_child () inherits (events);
|
|
|
|
explain (costs off)
|
|
|
|
select event_id
|
|
|
|
from (select event_id from events
|
|
|
|
union all
|
|
|
|
select event_id from other_events) ss
|
|
|
|
order by event_id;
|
|
|
|
QUERY PLAN
|
|
|
|
----------------------------------------------------------
|
|
|
|
Merge Append
|
|
|
|
Sort Key: events.event_id
|
|
|
|
-> Index Scan using events_pkey on events
|
|
|
|
-> Sort
|
|
|
|
Sort Key: events_child.event_id
|
|
|
|
-> Seq Scan on events_child
|
|
|
|
-> Index Scan using other_events_pkey on other_events
|
|
|
|
(7 rows)
|
|
|
|
|
|
|
|
drop table events_child, events, other_events;
|
2014-03-28 16:50:01 +01:00
|
|
|
reset enable_indexonlyscan;
|
Revisit handling of UNION ALL subqueries with non-Var output columns.
In commit 57664ed25e5dea117158a2e663c29e60b3546e1c I tried to fix a bug
reported by Teodor Sigaev by making non-simple-Var output columns distinct
(by wrapping their expressions with dummy PlaceHolderVar nodes). This did
not work too well. Commit b28ffd0fcc583c1811e5295279e7d4366c3cae6c fixed
some ensuing problems with matching to child indexes, but per a recent
report from Claus Stadler, constraint exclusion of UNION ALL subqueries was
still broken, because constant-simplification didn't handle the injected
PlaceHolderVars well either. On reflection, the original patch was quite
misguided: there is no reason to expect that EquivalenceClass child members
will be distinct. So instead of trying to make them so, we should ensure
that we can cope with the situation when they're not.
Accordingly, this patch reverts the code changes in the above-mentioned
commits (though the regression test cases they added stay). Instead, I've
added assorted defenses to make sure that duplicate EC child members don't
cause any problems. Teodor's original problem ("MergeAppend child's
targetlist doesn't match MergeAppend") is addressed more directly by
revising prepare_sort_from_pathkeys to let the parent MergeAppend's sort
list guide creation of each child's sort list.
In passing, get rid of add_sort_column; as far as I can tell, testing for
duplicate sort keys at this stage is dead code. Certainly it doesn't
trigger often enough to be worth expending cycles on in ordinary queries.
And keeping the test would've greatly complicated the new logic in
prepare_sort_from_pathkeys, because comparing pathkey list entries against
a previous output array requires that we not skip any entries in the list.
Back-patch to 9.1, like the previous patches. The only known issue in
this area that wasn't caused by the ill-advised previous patches was the
MergeAppend planning failure, which of course is not relevant before 9.1.
It's possible that we need some of the new defenses against duplicate child
EC entries in older branches, but until there's some clear evidence of that
I'm going to refrain from back-patching further.
2012-03-16 18:11:12 +01:00
|
|
|
-- Test constraint exclusion of UNION ALL subqueries
|
|
|
|
explain (costs off)
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT 1 AS t, * FROM tenk1 a
|
|
|
|
UNION ALL
|
|
|
|
SELECT 2 AS t, * FROM tenk1 b) c
|
|
|
|
WHERE t = 2;
|
Suppress Append and MergeAppend plan nodes that have a single child.
If there's only one child relation, the Append or MergeAppend isn't
doing anything useful, and can be elided. It does have a purpose
during planning though, which is to serve as a buffer between parent
and child Var numbering. Therefore we keep it all the way through
to setrefs.c, and get rid of it only after fixing references in the
plan level(s) above it. This works largely the same as setrefs.c's
ancient hack to get rid of no-op SubqueryScan nodes, and can even
share some code with that.
Note the change to make setrefs.c use apply_tlist_labeling rather than
ad-hoc code. This has the effect of propagating the child's resjunk
and ressortgroupref labels, which formerly weren't propagated when
removing a SubqueryScan. Doing that is demonstrably necessary for
the [Merge]Append cases, and seems harmless for SubqueryScan, if only
because trivial_subqueryscan is afraid to collapse cases where the
resjunk marking differs. (I suspect that restriction could now be
removed, though it's unclear that it'd make any new matches possible,
since the outer query can't have references to a child resjunk column.)
David Rowley, reviewed by Alvaro Herrera and Tomas Vondra
Discussion: https://postgr.es/m/CAKJS1f_7u8ATyJ1JGTMHFoKDvZdeF-iEBhs+sM_SXowOr9cArg@mail.gmail.com
2019-03-25 20:42:35 +01:00
|
|
|
QUERY PLAN
|
|
|
|
---------------------
|
|
|
|
Seq Scan on tenk1 b
|
|
|
|
(1 row)
|
Revisit handling of UNION ALL subqueries with non-Var output columns.
In commit 57664ed25e5dea117158a2e663c29e60b3546e1c I tried to fix a bug
reported by Teodor Sigaev by making non-simple-Var output columns distinct
(by wrapping their expressions with dummy PlaceHolderVar nodes). This did
not work too well. Commit b28ffd0fcc583c1811e5295279e7d4366c3cae6c fixed
some ensuing problems with matching to child indexes, but per a recent
report from Claus Stadler, constraint exclusion of UNION ALL subqueries was
still broken, because constant-simplification didn't handle the injected
PlaceHolderVars well either. On reflection, the original patch was quite
misguided: there is no reason to expect that EquivalenceClass child members
will be distinct. So instead of trying to make them so, we should ensure
that we can cope with the situation when they're not.
Accordingly, this patch reverts the code changes in the above-mentioned
commits (though the regression test cases they added stay). Instead, I've
added assorted defenses to make sure that duplicate EC child members don't
cause any problems. Teodor's original problem ("MergeAppend child's
targetlist doesn't match MergeAppend") is addressed more directly by
revising prepare_sort_from_pathkeys to let the parent MergeAppend's sort
list guide creation of each child's sort list.
In passing, get rid of add_sort_column; as far as I can tell, testing for
duplicate sort keys at this stage is dead code. Certainly it doesn't
trigger often enough to be worth expending cycles on in ordinary queries.
And keeping the test would've greatly complicated the new logic in
prepare_sort_from_pathkeys, because comparing pathkey list entries against
a previous output array requires that we not skip any entries in the list.
Back-patch to 9.1, like the previous patches. The only known issue in
this area that wasn't caused by the ill-advised previous patches was the
MergeAppend planning failure, which of course is not relevant before 9.1.
It's possible that we need some of the new defenses against duplicate child
EC entries in older branches, but until there's some clear evidence of that
I'm going to refrain from back-patching further.
2012-03-16 18:11:12 +01:00
|
|
|
|
2013-06-06 05:44:02 +02:00
|
|
|
-- Test that we push quals into UNION sub-selects only when it's safe
|
|
|
|
explain (costs off)
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT 1 AS t, 2 AS x
|
|
|
|
UNION
|
|
|
|
SELECT 2 AS t, 4 AS x) ss
|
2016-10-10 22:41:57 +02:00
|
|
|
WHERE x < 4
|
|
|
|
ORDER BY x;
|
|
|
|
QUERY PLAN
|
|
|
|
--------------------------------------------------
|
|
|
|
Sort
|
|
|
|
Sort Key: (2)
|
|
|
|
-> Unique
|
|
|
|
-> Sort
|
|
|
|
Sort Key: (1), (2)
|
|
|
|
-> Append
|
|
|
|
-> Result
|
|
|
|
-> Result
|
|
|
|
One-Time Filter: false
|
|
|
|
(9 rows)
|
2013-06-06 05:44:02 +02:00
|
|
|
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT 1 AS t, 2 AS x
|
|
|
|
UNION
|
|
|
|
SELECT 2 AS t, 4 AS x) ss
|
2016-10-10 22:41:57 +02:00
|
|
|
WHERE x < 4
|
|
|
|
ORDER BY x;
|
2013-06-06 05:44:02 +02:00
|
|
|
t | x
|
|
|
|
---+---
|
|
|
|
1 | 2
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
explain (costs off)
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT 1 AS t, generate_series(1,10) AS x
|
|
|
|
UNION
|
|
|
|
SELECT 2 AS t, 4 AS x) ss
|
|
|
|
WHERE x < 4
|
|
|
|
ORDER BY x;
|
2013-12-12 17:24:38 +01:00
|
|
|
QUERY PLAN
|
|
|
|
--------------------------------------------------------
|
2013-06-06 05:44:02 +02:00
|
|
|
Sort
|
|
|
|
Sort Key: ss.x
|
|
|
|
-> Subquery Scan on ss
|
|
|
|
Filter: (ss.x < 4)
|
|
|
|
-> HashAggregate
|
2013-12-12 17:24:38 +01:00
|
|
|
Group Key: (1), (generate_series(1, 10))
|
2013-06-06 05:44:02 +02:00
|
|
|
-> Append
|
Move targetlist SRF handling from expression evaluation to new executor node.
Evaluation of set returning functions (SRFs_ in the targetlist (like SELECT
generate_series(1,5)) so far was done in the expression evaluation (i.e.
ExecEvalExpr()) and projection (i.e. ExecProject/ExecTargetList) code.
This meant that most executor nodes performing projection, and most
expression evaluation functions, had to deal with the possibility that an
evaluated expression could return a set of return values.
That's bad because it leads to repeated code in a lot of places. It also,
and that's my (Andres's) motivation, made it a lot harder to implement a
more efficient way of doing expression evaluation.
To fix this, introduce a new executor node (ProjectSet) that can evaluate
targetlists containing one or more SRFs. To avoid the complexity of the old
way of handling nested expressions returning sets (e.g. having to pass up
ExprDoneCond, and dealing with arguments to functions returning sets etc.),
those SRFs can only be at the top level of the node's targetlist. The
planner makes sure (via split_pathtarget_at_srfs()) that SRF evaluation is
only necessary in ProjectSet nodes and that SRFs are only present at the
top level of the node's targetlist. If there are nested SRFs the planner
creates multiple stacked ProjectSet nodes. The ProjectSet nodes always get
input from an underlying node.
We also discussed and prototyped evaluating targetlist SRFs using ROWS
FROM(), but that turned out to be more complicated than we'd hoped.
While moving SRF evaluation to ProjectSet would allow to retain the old
"least common multiple" behavior when multiple SRFs are present in one
targetlist (i.e. continue returning rows until all SRFs are at the end of
their input at the same time), we decided to instead only return rows till
all SRFs are exhausted, returning NULL for already exhausted ones. We
deemed the previous behavior to be too confusing, unexpected and actually
not particularly useful.
As a side effect, the previously prohibited case of multiple set returning
arguments to a function, is now allowed. Not because it's particularly
desirable, but because it ends up working and there seems to be no argument
for adding code to prohibit it.
Currently the behavior for COALESCE and CASE containing SRFs has changed,
returning multiple rows from the expression, even when the SRF containing
"arm" of the expression is not evaluated. That's because the SRFs are
evaluated in a separate ProjectSet node. As that's quite confusing, we're
likely to instead prohibit SRFs in those places. But that's still being
discussed, and the code would reside in places not touched here, so that's
a task for later.
There's a lot of, now superfluous, code dealing with set return expressions
around. But as the changes to get rid of those are verbose largely boring,
it seems better for readability to keep the cleanup as a separate commit.
Author: Tom Lane and Andres Freund
Discussion: https://postgr.es/m/20160822214023.aaxz5l4igypowyri@alap3.anarazel.de
2017-01-18 21:46:50 +01:00
|
|
|
-> ProjectSet
|
|
|
|
-> Result
|
2013-06-06 05:44:02 +02:00
|
|
|
-> Result
|
Move targetlist SRF handling from expression evaluation to new executor node.
Evaluation of set returning functions (SRFs_ in the targetlist (like SELECT
generate_series(1,5)) so far was done in the expression evaluation (i.e.
ExecEvalExpr()) and projection (i.e. ExecProject/ExecTargetList) code.
This meant that most executor nodes performing projection, and most
expression evaluation functions, had to deal with the possibility that an
evaluated expression could return a set of return values.
That's bad because it leads to repeated code in a lot of places. It also,
and that's my (Andres's) motivation, made it a lot harder to implement a
more efficient way of doing expression evaluation.
To fix this, introduce a new executor node (ProjectSet) that can evaluate
targetlists containing one or more SRFs. To avoid the complexity of the old
way of handling nested expressions returning sets (e.g. having to pass up
ExprDoneCond, and dealing with arguments to functions returning sets etc.),
those SRFs can only be at the top level of the node's targetlist. The
planner makes sure (via split_pathtarget_at_srfs()) that SRF evaluation is
only necessary in ProjectSet nodes and that SRFs are only present at the
top level of the node's targetlist. If there are nested SRFs the planner
creates multiple stacked ProjectSet nodes. The ProjectSet nodes always get
input from an underlying node.
We also discussed and prototyped evaluating targetlist SRFs using ROWS
FROM(), but that turned out to be more complicated than we'd hoped.
While moving SRF evaluation to ProjectSet would allow to retain the old
"least common multiple" behavior when multiple SRFs are present in one
targetlist (i.e. continue returning rows until all SRFs are at the end of
their input at the same time), we decided to instead only return rows till
all SRFs are exhausted, returning NULL for already exhausted ones. We
deemed the previous behavior to be too confusing, unexpected and actually
not particularly useful.
As a side effect, the previously prohibited case of multiple set returning
arguments to a function, is now allowed. Not because it's particularly
desirable, but because it ends up working and there seems to be no argument
for adding code to prohibit it.
Currently the behavior for COALESCE and CASE containing SRFs has changed,
returning multiple rows from the expression, even when the SRF containing
"arm" of the expression is not evaluated. That's because the SRFs are
evaluated in a separate ProjectSet node. As that's quite confusing, we're
likely to instead prohibit SRFs in those places. But that's still being
discussed, and the code would reside in places not touched here, so that's
a task for later.
There's a lot of, now superfluous, code dealing with set return expressions
around. But as the changes to get rid of those are verbose largely boring,
it seems better for readability to keep the cleanup as a separate commit.
Author: Tom Lane and Andres Freund
Discussion: https://postgr.es/m/20160822214023.aaxz5l4igypowyri@alap3.anarazel.de
2017-01-18 21:46:50 +01:00
|
|
|
(10 rows)
|
2013-06-06 05:44:02 +02:00
|
|
|
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT 1 AS t, generate_series(1,10) AS x
|
|
|
|
UNION
|
|
|
|
SELECT 2 AS t, 4 AS x) ss
|
|
|
|
WHERE x < 4
|
|
|
|
ORDER BY x;
|
|
|
|
t | x
|
|
|
|
---+---
|
|
|
|
1 | 1
|
|
|
|
1 | 2
|
|
|
|
1 | 3
|
|
|
|
(3 rows)
|
|
|
|
|
|
|
|
explain (costs off)
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT 1 AS t, (random()*3)::int AS x
|
|
|
|
UNION
|
|
|
|
SELECT 2 AS t, 4 AS x) ss
|
2016-10-10 22:41:57 +02:00
|
|
|
WHERE x > 3
|
|
|
|
ORDER BY x;
|
|
|
|
QUERY PLAN
|
|
|
|
------------------------------------------------------------------------------------
|
|
|
|
Sort
|
|
|
|
Sort Key: ss.x
|
|
|
|
-> Subquery Scan on ss
|
|
|
|
Filter: (ss.x > 3)
|
|
|
|
-> Unique
|
|
|
|
-> Sort
|
|
|
|
Sort Key: (1), (((random() * '3'::double precision))::integer)
|
|
|
|
-> Append
|
|
|
|
-> Result
|
|
|
|
-> Result
|
|
|
|
(10 rows)
|
2013-06-06 05:44:02 +02:00
|
|
|
|
|
|
|
SELECT * FROM
|
|
|
|
(SELECT 1 AS t, (random()*3)::int AS x
|
|
|
|
UNION
|
|
|
|
SELECT 2 AS t, 4 AS x) ss
|
2016-10-10 22:41:57 +02:00
|
|
|
WHERE x > 3
|
|
|
|
ORDER BY x;
|
2013-06-06 05:44:02 +02:00
|
|
|
t | x
|
|
|
|
---+---
|
|
|
|
2 | 4
|
|
|
|
(1 row)
|
|
|
|
|
2013-07-08 04:37:24 +02:00
|
|
|
-- Test proper handling of parameterized appendrel paths when the
|
|
|
|
-- potential join qual is expensive
|
|
|
|
create function expensivefunc(int) returns int
|
|
|
|
language plpgsql immutable strict cost 10000
|
|
|
|
as $$begin return $1; end$$;
|
|
|
|
create temp table t3 as select generate_series(-1000,1000) as x;
|
|
|
|
create index t3i on t3 (expensivefunc(x));
|
|
|
|
analyze t3;
|
|
|
|
explain (costs off)
|
|
|
|
select * from
|
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(select * from t3 a union all select * from t3 b) ss
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join int4_tbl on f1 = expensivefunc(x);
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QUERY PLAN
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------------------------------------------------------------
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Nested Loop
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-> Seq Scan on int4_tbl
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-> Append
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-> Index Scan using t3i on t3 a
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Index Cond: (expensivefunc(x) = int4_tbl.f1)
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-> Index Scan using t3i on t3 b
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Index Cond: (expensivefunc(x) = int4_tbl.f1)
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(7 rows)
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select * from
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(select * from t3 a union all select * from t3 b) ss
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join int4_tbl on f1 = expensivefunc(x);
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|
x | f1
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---+----
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0 | 0
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0 | 0
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(2 rows)
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drop table t3;
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drop function expensivefunc(int);
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2017-01-20 00:20:48 +01:00
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|
|
-- Test handling of appendrel quals that const-simplify into an AND
|
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|
|
explain (costs off)
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|
|
select * from
|
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|
|
(select *, 0 as x from int8_tbl a
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|
union all
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|
|
select *, 1 as x from int8_tbl b) ss
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where (x = 0) or (q1 >= q2 and q1 <= q2);
|
|
|
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QUERY PLAN
|
|
|
|
---------------------------------------------
|
|
|
|
Append
|
|
|
|
-> Seq Scan on int8_tbl a
|
|
|
|
-> Seq Scan on int8_tbl b
|
|
|
|
Filter: ((q1 >= q2) AND (q1 <= q2))
|
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|
(4 rows)
|
|
|
|
|
|
|
|
select * from
|
|
|
|
(select *, 0 as x from int8_tbl a
|
|
|
|
union all
|
|
|
|
select *, 1 as x from int8_tbl b) ss
|
|
|
|
where (x = 0) or (q1 >= q2 and q1 <= q2);
|
|
|
|
q1 | q2 | x
|
|
|
|
------------------+-------------------+---
|
|
|
|
123 | 456 | 0
|
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|
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123 | 4567890123456789 | 0
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|
4567890123456789 | 123 | 0
|
|
|
|
4567890123456789 | 4567890123456789 | 0
|
|
|
|
4567890123456789 | -4567890123456789 | 0
|
|
|
|
4567890123456789 | 4567890123456789 | 1
|
|
|
|
(6 rows)
|
|
|
|
|