mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-10-01 06:41:46 +02:00
be8100d64e
Patch from Pavel Stehule, minor fixups by myself.
223 lines
3.3 KiB
Plaintext
223 lines
3.3 KiB
Plaintext
--
|
|
-- SELECT_DISTINCT
|
|
--
|
|
--
|
|
-- awk '{print $3;}' onek.data | sort -n | uniq
|
|
--
|
|
SELECT DISTINCT two FROM tmp;
|
|
two
|
|
-----
|
|
0
|
|
1
|
|
(2 rows)
|
|
|
|
--
|
|
-- awk '{print $5;}' onek.data | sort -n | uniq
|
|
--
|
|
SELECT DISTINCT ten FROM tmp;
|
|
ten
|
|
-----
|
|
0
|
|
1
|
|
2
|
|
3
|
|
4
|
|
5
|
|
6
|
|
7
|
|
8
|
|
9
|
|
(10 rows)
|
|
|
|
--
|
|
-- awk '{print $16;}' onek.data | sort -d | uniq
|
|
--
|
|
SELECT DISTINCT string4 FROM tmp;
|
|
string4
|
|
---------
|
|
AAAAxx
|
|
HHHHxx
|
|
OOOOxx
|
|
VVVVxx
|
|
(4 rows)
|
|
|
|
--
|
|
-- awk '{print $3,$16,$5;}' onek.data | sort -d | uniq |
|
|
-- sort +0n -1 +1d -2 +2n -3
|
|
--
|
|
SELECT DISTINCT two, string4, ten
|
|
FROM tmp
|
|
ORDER BY two using <, string4 using <, ten using <;
|
|
two | string4 | ten
|
|
-----+---------+-----
|
|
0 | AAAAxx | 0
|
|
0 | AAAAxx | 2
|
|
0 | AAAAxx | 4
|
|
0 | AAAAxx | 6
|
|
0 | AAAAxx | 8
|
|
0 | HHHHxx | 0
|
|
0 | HHHHxx | 2
|
|
0 | HHHHxx | 4
|
|
0 | HHHHxx | 6
|
|
0 | HHHHxx | 8
|
|
0 | OOOOxx | 0
|
|
0 | OOOOxx | 2
|
|
0 | OOOOxx | 4
|
|
0 | OOOOxx | 6
|
|
0 | OOOOxx | 8
|
|
0 | VVVVxx | 0
|
|
0 | VVVVxx | 2
|
|
0 | VVVVxx | 4
|
|
0 | VVVVxx | 6
|
|
0 | VVVVxx | 8
|
|
1 | AAAAxx | 1
|
|
1 | AAAAxx | 3
|
|
1 | AAAAxx | 5
|
|
1 | AAAAxx | 7
|
|
1 | AAAAxx | 9
|
|
1 | HHHHxx | 1
|
|
1 | HHHHxx | 3
|
|
1 | HHHHxx | 5
|
|
1 | HHHHxx | 7
|
|
1 | HHHHxx | 9
|
|
1 | OOOOxx | 1
|
|
1 | OOOOxx | 3
|
|
1 | OOOOxx | 5
|
|
1 | OOOOxx | 7
|
|
1 | OOOOxx | 9
|
|
1 | VVVVxx | 1
|
|
1 | VVVVxx | 3
|
|
1 | VVVVxx | 5
|
|
1 | VVVVxx | 7
|
|
1 | VVVVxx | 9
|
|
(40 rows)
|
|
|
|
--
|
|
-- awk '{print $2;}' person.data |
|
|
-- awk '{if(NF!=1){print $2;}else{print;}}' - emp.data |
|
|
-- awk '{if(NF!=1){print $2;}else{print;}}' - student.data |
|
|
-- awk 'BEGIN{FS=" ";}{if(NF!=1){print $5;}else{print;}}' - stud_emp.data |
|
|
-- sort -n -r | uniq
|
|
--
|
|
SELECT DISTINCT p.age FROM person* p ORDER BY age using >;
|
|
age
|
|
-----
|
|
98
|
|
88
|
|
78
|
|
68
|
|
60
|
|
58
|
|
50
|
|
48
|
|
40
|
|
38
|
|
34
|
|
30
|
|
28
|
|
25
|
|
24
|
|
23
|
|
20
|
|
19
|
|
18
|
|
8
|
|
(20 rows)
|
|
|
|
--
|
|
-- Also, some tests of IS DISTINCT FROM, which doesn't quite deserve its
|
|
-- very own regression file.
|
|
--
|
|
CREATE TEMP TABLE disttable (f1 integer);
|
|
INSERT INTO DISTTABLE VALUES(1);
|
|
INSERT INTO DISTTABLE VALUES(2);
|
|
INSERT INTO DISTTABLE VALUES(3);
|
|
INSERT INTO DISTTABLE VALUES(NULL);
|
|
-- basic cases
|
|
SELECT f1, f1 IS DISTINCT FROM 2 as "not 2" FROM disttable;
|
|
f1 | not 2
|
|
----+-------
|
|
1 | t
|
|
2 | f
|
|
3 | t
|
|
| t
|
|
(4 rows)
|
|
|
|
SELECT f1, f1 IS DISTINCT FROM NULL as "not null" FROM disttable;
|
|
f1 | not null
|
|
----+----------
|
|
1 | t
|
|
2 | t
|
|
3 | t
|
|
| f
|
|
(4 rows)
|
|
|
|
SELECT f1, f1 IS DISTINCT FROM f1 as "false" FROM disttable;
|
|
f1 | false
|
|
----+-------
|
|
1 | f
|
|
2 | f
|
|
3 | f
|
|
| f
|
|
(4 rows)
|
|
|
|
SELECT f1, f1 IS DISTINCT FROM f1+1 as "not null" FROM disttable;
|
|
f1 | not null
|
|
----+----------
|
|
1 | t
|
|
2 | t
|
|
3 | t
|
|
| f
|
|
(4 rows)
|
|
|
|
-- check that optimizer constant-folds it properly
|
|
SELECT 1 IS DISTINCT FROM 2 as "yes";
|
|
yes
|
|
-----
|
|
t
|
|
(1 row)
|
|
|
|
SELECT 2 IS DISTINCT FROM 2 as "no";
|
|
no
|
|
----
|
|
f
|
|
(1 row)
|
|
|
|
SELECT 2 IS DISTINCT FROM null as "yes";
|
|
yes
|
|
-----
|
|
t
|
|
(1 row)
|
|
|
|
SELECT null IS DISTINCT FROM null as "no";
|
|
no
|
|
----
|
|
f
|
|
(1 row)
|
|
|
|
-- ANSI SQL 2003 form
|
|
SELECT 1 IS NOT DISTINCT FROM 2 as "no";
|
|
no
|
|
----
|
|
f
|
|
(1 row)
|
|
|
|
SELECT 2 IS NOT DISTINCT FROM 2 as "yes";
|
|
yes
|
|
-----
|
|
t
|
|
(1 row)
|
|
|
|
SELECT 2 IS NOT DISTINCT FROM null as "no";
|
|
no
|
|
----
|
|
f
|
|
(1 row)
|
|
|
|
SELECT null IS NOT DISTINCT FROM null as "yes";
|
|
yes
|
|
-----
|
|
t
|
|
(1 row)
|
|
|