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Date: 2019-07-11 15:07:53 +0200 From: @swingbit To: SQL devs <> Version: 11.31.13 (Aug2018-SP2) CC: @njnes, @PedroTadim
Last updated: 2019-09-02 16:05:26 +0200
Date: 2019-07-11 15:07:53 +0200 From: @swingbit
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36 Build Identifier:
start transaction;
create table r(a1 string, a2 string); insert into r values ('a','b'), ('a','b'), ('b','a');
The following query removes duplicate correctly:
SELECT DISTINCT a1,a2 FROM r;
+------+------+ | a1 | a2 | +======+======+ | a | b | | b | a | +------+------+ 2 tuples
The following query doesn't:
SELECT DISTINCT CASE WHEN a1 > a2 THEN a2 ELSE a1 END as c1, CASE WHEN a1 < a2 THEN a2 ELSE a1 END as c2 FROM r;
+------+------+ | c1 | c2 | +======+======+ | a | b | | a | b | +------+------+ 2 tuples
It's not really important what the CASE statements do. The DISTINCT should remove duplicate rows from the final relation, but they are still there.
Reproducible: Always
Date: 2019-07-11 15:11:31 +0200 From: @swingbit
Also notice that replacing DISTINCT with the corresponding GROUP BY clause gives the correct result:
SELECT CASE WHEN a1 > a2 THEN a2 ELSE a1 END as c1, CASE WHEN a1 < a2 THEN a2 ELSE a1 END as c2 FROM r GROUP BY c1,c2;
+------+------+ | c1 | c2 | +======+======+ | a | b | +------+------+ 1 tuple
Date: 2019-07-11 15:59:03 +0200 From: @PedroTadim
This bug is reproducible on Apr2019 branch, but not on default.
Date: 2019-07-11 18:22:57 +0200 From: MonetDB Mercurial Repository <>
Changeset 4448a5aee0a4 made by Pedro Ferreira pedro.ferreira@monetdbsolutions.com in the MonetDB repo, refers to this bug.
For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=4448a5aee0a4
Changeset description:
Added test bug #6728.
Date: 2019-07-27 22:47:07 +0200 From: MonetDB Mercurial Repository <>
Changeset 397669aa4038 made by Niels Nes niels@cwi.nl in the MonetDB repo, refers to this bug.
For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=397669aa4038
make sure we do not loose the distinct when rewriting (splitting) the project expressions. This fixes bug #6728
Date: 2019-07-27 22:47:34 +0200 From: @njnes
fixed optimizer
The text was updated successfully, but these errors were encountered:
No branches or pull requests
Date: 2019-07-11 15:07:53 +0200
From: @swingbit
To: SQL devs <>
Version: 11.31.13 (Aug2018-SP2)
CC: @njnes, @PedroTadim
Last updated: 2019-09-02 16:05:26 +0200
Comment 27127
Date: 2019-07-11 15:07:53 +0200
From: @swingbit
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36
Build Identifier:
start transaction;
create table r(a1 string, a2 string);
insert into r values
('a','b'),
('a','b'),
('b','a');
The following query removes duplicate correctly:
SELECT DISTINCT a1,a2
FROM r;
+------+------+
| a1 | a2 |
+======+======+
| a | b |
| b | a |
+------+------+
2 tuples
The following query doesn't:
SELECT DISTINCT
CASE WHEN a1 > a2 THEN a2 ELSE a1 END as c1,
CASE WHEN a1 < a2 THEN a2 ELSE a1 END as c2
FROM r;
+------+------+
| c1 | c2 |
+======+======+
| a | b |
| a | b |
+------+------+
2 tuples
It's not really important what the CASE statements do. The DISTINCT should remove duplicate rows from the final relation, but they are still there.
Reproducible: Always
Comment 27128
Date: 2019-07-11 15:11:31 +0200
From: @swingbit
Also notice that replacing DISTINCT with the corresponding GROUP BY clause gives the correct result:
SELECT
CASE WHEN a1 > a2 THEN a2 ELSE a1 END as c1,
CASE WHEN a1 < a2 THEN a2 ELSE a1 END as c2
FROM r
GROUP BY c1,c2;
+------+------+
| c1 | c2 |
+======+======+
| a | b |
+------+------+
1 tuple
Comment 27129
Date: 2019-07-11 15:59:03 +0200
From: @PedroTadim
This bug is reproducible on Apr2019 branch, but not on default.
Comment 27132
Date: 2019-07-11 18:22:57 +0200
From: MonetDB Mercurial Repository <>
Changeset 4448a5aee0a4 made by Pedro Ferreira pedro.ferreira@monetdbsolutions.com in the MonetDB repo, refers to this bug.
For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=4448a5aee0a4
Changeset description:
Comment 27178
Date: 2019-07-27 22:47:07 +0200
From: MonetDB Mercurial Repository <>
Changeset 397669aa4038 made by Niels Nes niels@cwi.nl in the MonetDB repo, refers to this bug.
For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=397669aa4038
Changeset description:
Comment 27179
Date: 2019-07-27 22:47:34 +0200
From: @njnes
fixed optimizer
The text was updated successfully, but these errors were encountered: