1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (a BIT <CUSTOM_COL_OPTIONS>,
b BIT(20) <CUSTOM_COL_OPTIONS>,
c BIT(32) <CUSTOM_COL_OPTIONS>,
d BIT(64) <CUSTOM_COL_OPTIONS>,
<CUSTOM_INDEX> b (b)
) ENGINE=<STORAGE_ENGINE> <CUSTOM_TABLE_OPTIONS>;
SHOW INDEX IN t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 1 # 1 b # # NULL NULL # #
INSERT INTO t1 (a,b,c,d) VALUES
(0,0xFFFFF,0,1),(0,256,0xAAA,0x12345),(1,16,0,0xFFFFFFF),(0,11,12,13),
(1,100,101,102),(0,12,13,14),(1,13,14,15),(0,101,201,202),(1,1000,1001,1002),
(1,0xFFFF,0xFFFFFFFF,0xFFFFFFFFFFFFFFFF);
SELECT b+0 FROM t1 ORDER BY b;
b+0
11
12
13
16
100
101
256
1000
65535
1048575
DROP TABLE t1;
CREATE TABLE t1 (a BIT <CUSTOM_COL_OPTIONS>,
b BIT(20) <CUSTOM_COL_OPTIONS> PRIMARY KEY,
c BIT(32) <CUSTOM_COL_OPTIONS>,
d BIT(64) <CUSTOM_COL_OPTIONS>
) ENGINE=<STORAGE_ENGINE> <CUSTOM_TABLE_OPTIONS>;
SHOW INDEX IN t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 0 PRIMARY 1 b # # NULL NULL # #
INSERT INTO t1 (a,b,c,d) VALUES
(0,0xFFFFF,0,1),(0,256,0xAAA,0x12345),(1,16,0,0xFFFFFFF),(0,11,12,13),
(1,100,101,102),(0,12,13,14),(1,13,14,15),(0,101,201,202),(1,1000,1001,1002),
(1,0xFFFF,0xFFFFFFFF,0xFFFFFFFFFFFFFFFF);
EXPLAIN SELECT b+0 FROM t1 ORDER BY b;
id select_type table type possible_keys key key_len ref rows Extra
# # # # # PRIMARY # # # #
SELECT b+0 FROM t1 ORDER BY b;
b+0
11
12
13
16
100
101
256
1000
65535
1048575
DROP TABLE t1;
CREATE TABLE t1 (a BIT <CUSTOM_COL_OPTIONS>,
b BIT(20) <CUSTOM_COL_OPTIONS>,
c BIT(32) <CUSTOM_COL_OPTIONS>,
d BIT(64) <CUSTOM_COL_OPTIONS>,
UNIQUE INDEX b_c (b,c)
) ENGINE=<STORAGE_ENGINE> <CUSTOM_TABLE_OPTIONS>;
SHOW INDEX IN t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 0 b_c 1 b # # NULL NULL # #
t1 0 b_c 2 c # # NULL NULL # #
INSERT INTO t1 (a,b,c,d) VALUES
(0,0xFFFFF,0,1),(0,256,0xAAA,0x12345),(1,16,0,0xFFFFFFF),(0,11,12,13),
(1,100,101,102),(0,12,13,14),(1,13,14,15),(0,101,201,202),(1,1000,1001,1002),
(1,0xFFFF,0xFFFFFFFF,0xFFFFFFFFFFFFFFFF);
EXPLAIN SELECT HEX(b+c) FROM t1 WHERE c > 1 OR HEX(b) < 0xFFFFFF;
id select_type table type possible_keys key key_len ref rows Extra
# # # # # b_c # # # #
SELECT HEX(b+c) FROM t1 WHERE c > 1 OR HEX(b) < 0xFFFFFF;
HEX(b+c)
10
10000FFFE
12E
17
19
1B
7D1
BAA
C9
FFFFF
DROP TABLE t1;
CREATE TABLE t1 (a BIT <CUSTOM_COL_OPTIONS>,
b BIT(20) <CUSTOM_COL_OPTIONS>,
c BIT(32) <CUSTOM_COL_OPTIONS>,
d BIT(64) <CUSTOM_COL_OPTIONS>,
INDEX(a)
) ENGINE=<STORAGE_ENGINE> <CUSTOM_TABLE_OPTIONS>;
SHOW INDEX IN t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 1 a 1 a # # NULL NULL # #
INSERT INTO t1 (a,b,c,d) VALUES
(0,0xFFFFF,0,1),(0,256,0xAAA,0x12345),(1,16,0,0xFFFFFFF),(0,11,12,13),
(1,100,101,102),(0,12,13,14),(1,13,14,15),(0,101,201,202),(1,1000,1001,1002),
(1,0xFFFF,0xFFFFFFFF,0xFFFFFFFFFFFFFFFF);
EXPLAIN SELECT DISTINCT a+0 FROM t1 ORDER BY a;
id select_type table type possible_keys key key_len ref rows Extra
# # # # # a # # # #
SELECT DISTINCT a+0 FROM t1 ORDER BY a;
a+0
0
1
DROP TABLE t1;
CREATE TABLE t1 (a BIT <CUSTOM_COL_OPTIONS>,
b BIT(20) <CUSTOM_COL_OPTIONS>,
c BIT(32) <CUSTOM_COL_OPTIONS>,
d BIT(64) <CUSTOM_COL_OPTIONS>,
UNIQUE INDEX (d)
) ENGINE=<STORAGE_ENGINE> <CUSTOM_TABLE_OPTIONS>;
SHOW INDEX IN t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 0 d 1 d # # NULL NULL # #
INSERT INTO t1 (a,b,c,d) VALUES
(0,0xFFFFF,0,1),(0,256,0xAAA,0x12345),(1,16,0,0xFFFFFFF),(0,11,12,13),
(1,100,101,102),(0,12,13,14),(1,13,14,15),(0,101,201,202),(1,1000,1001,1002),
(1,0xFFFF,0xFFFFFFFF,0xFFFFFFFFFFFFFFFF);
EXPLAIN SELECT d FROM t1 WHERE d BETWEEN 1 AND 10000;
id select_type table type possible_keys key key_len ref rows Extra
# # # # # d # # # #
SELECT d+0 FROM t1 WHERE d BETWEEN 1 AND 10000;
d+0
1
1002
102
13
14
15
202
DROP TABLE t1;
|
