SET NAMES utf8mb4;
SELECT NATURAL_SORT_KEY(NULL);
NATURAL_SORT_KEY(NULL)
NULL
SELECT NATURAL_SORT_KEY(repeat('a1',@@max_allowed_packet/2-1));
NATURAL_SORT_KEY(repeat('a1',@@max_allowed_packet/2-1))
NULL
Warnings:
Warning 1301 Result of natural_sort_key() was larger than max_allowed_packet (16777216) - truncated
SELECT NATURAL_SORT_KEY(repeat('1',@@max_allowed_packet-1));
NATURAL_SORT_KEY(repeat('1',@@max_allowed_packet-1))
NULL
Warnings:
Warning 1301 Result of natural_sort_key() was larger than max_allowed_packet (16777216) - truncated
CREATE TABLE t1(
c VARCHAR(30) CHARACTER SET latin1 COLLATE latin1_bin,
k VARCHAR(60) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci AS (NATURAL_SORT_KEY(CONVERT(c USING utf8mb4))) VIRTUAL INVISIBLE);
INSERT INTO t1 values
('A1'),('a1'),('A100'),('a100'),('A2'),('ä2'),('a2'),('A99'),
('äb'),('B1'),('B100'),('B9'),('C'),('100');
#Natural sort order.
SELECT c FROM t1 ORDER BY k,c;
c
100
A1
a1
A2
a2
ä2
A99
A100
a100
äb
B1
B9
B100
C
#Unnatural but  unicode aware) sort order
SELECT c FROM t1 ORDER BY CONVERT(c USING utf8mb4) COLLATE utf8mb4_unicode_ci,c;
c
100
A1
a1
A100
a100
A2
a2
ä2
A99
äb
B1
B100
B9
C
CREATE TABLE t2 AS SELECT c, NATURAL_SORT_KEY(c) FROM t1 WHERE 0;
SHOW CREATE TABLE t2;
Table Create Table
t2 CREATE TABLE `t2` (
  `c` varchar(30) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,
  `NATURAL_SORT_KEY(c)` varchar(45) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
DROP TABLE t1,t2;
CREATE TABLE t1(c VARCHAR(1), k VARCHAR(2) AS (NATURAL_SORT_KEY(c)) STORED);
ERROR HY000: Function or expression 'natural_sort_key()' cannot be used in the GENERATED ALWAYS AS clause of `k`
SELECT RPAD(val,28,' ') value , RPAD(NATURAL_SORT_KEY(val),36,' ') sortkey , LENGTH(NATURAL_SORT_KEY(val)) - LENGTH(val) encoding_overhead
FROM
(
SELECT '0' val
UNION  SELECT seq FROM seq_1_to_9
UNION  SELECT CONCAT('1',repeat('0',seq)) FROM seq_1_to_27
) AS numbers ORDER BY sortkey;
value sortkey encoding_overhead
0                            00                                   1
1                            01                                   1
2                            02                                   1
3                            03                                   1
4                            04                                   1
5                            05                                   1
6                            06                                   1
7                            07                                   1
8                            08                                   1
9                            09                                   1
10                           110                                  1
100                          2100                                 1
1000                         31000                                1
10000                        410000                               1
100000                       5100000                              1
1000000                      61000000                             1
10000000                     710000000                            1
100000000                    8100000000                           1
1000000000                   901000000000                         2
10000000000                  9110000000000                        2
100000000000                 92100000000000                       2
1000000000000                931000000000000                      2
10000000000000               9410000000000000                     2
100000000000000              95100000000000000                    2
1000000000000000             961000000000000000                   2
10000000000000000            9710000000000000000                  2
100000000000000000           98100000000000000000                 2
1000000000000000000          9901000000000000000000               3
10000000000000000000         99110000000000000000000              3
100000000000000000000        992100000000000000000000             3
1000000000000000000000       9931000000000000000000000            3
10000000000000000000000      99410000000000000000000000           3
100000000000000000000000     995100000000000000000000000          3
1000000000000000000000000    9961000000000000000000000000         3
10000000000000000000000000   99710000000000000000000000000        3
100000000000000000000000000  998100000000000000000000000000       3
1000000000000000000000000000 99901271000000000000000000000000000  7
SELECT natural_sort_key('1') = natural_sort_key('0001');
natural_sort_key('1') = natural_sort_key('0001')
1
SELECT natural_sort_key('1.1') = natural_sort_key('1.00001');
natural_sort_key('1.1') = natural_sort_key('1.00001')
1
SELECT RPAD(val,20,' ') value, NATURAL_SORT_KEY(val) FROM
(SELECT '' val WHERE 0 UNION VALUES
('fred'),
('pic2'),
('pic100a'),
('pic120'),
('pic121'),
('jane'),
('tom'),
('pic02a'),
('pic3'),
('pic4'),
('1-20'),
('pic100'),
('pic02000'),
('10-20'),
('1-02'),
('1-2'),
('pic01'),
('pic02'),
('pic 6'),
('pic   7'),
('pic 5'),
('pic05'),
('pic 5 '),
('pic 5 something'),
('pic 4 else'),
('2000-1-10'),
('1999-12-25'),
('1999-3-3'),
('2000-3-23'),
('2000-1-2'),
('100.200.300.400'),
('100.50.60.70'),
('100.8.9.0'),
('a1b1'),
('a01b2'),
('a1b2'),
('a01b3')
)AS data ORDER BY 2,1;
value NATURAL_SORT_KEY(val)
1-02                 01-02
1-2                  01-02
1-20                 01-120
10-20                110-120
100.8.9.0            2100.08.09.00
100.50.60.70         2100.150.160.170
100.200.300.400      2100.2200.2300.2400
1999-3-3             31999-03-03
1999-12-25           31999-112-125
2000-1-2             32000-01-02
2000-1-10            32000-01-110
2000-3-23            32000-03-123
a1b1                 a01b01
a01b2                a01b02
a1b2                 a01b02
a01b3                a01b03
fred                 fred
jane                 jane
pic   7              pic   07
pic 4 else           pic 04 else
pic 5                pic 05
pic 5 something      pic 05 something
pic 6                pic 06
pic01                pic01
pic02                pic02
pic2                 pic02
pic02a               pic02a
pic3                 pic03
pic4                 pic04
pic05                pic05
pic100               pic2100
pic100a              pic2100a
pic120               pic2120
pic121               pic2121
pic02000             pic32000
tom                  tom
create table t (a varchar(8), b varchar(8) as (natural_sort_key(a)));
insert into t (a) values ('a2'),(NULL),('a11');
select * from t order by b;
a b
NULL NULL
a2 a02
a11 a111
select a, b from t order by b;
a b
NULL NULL
a2 a02
a11 a111
drop table t;
select natural_sort_key(_utf16 0x0031),natural_sort_key(_ucs2 0x0031), natural_sort_key(_utf32 0x00000031);
natural_sort_key(_utf16 0x0031) natural_sort_key(_ucs2 0x0031) natural_sort_key(_utf32 0x00000031)
01 01 01
select get_lock('a', 0);
get_lock('a', 0)
1
select natural_sort_key(release_lock('a'));
natural_sort_key(release_lock('a'))
01