回答編集履歴
4
ちょうせい
test
CHANGED
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@@ -33,8 +33,6 @@
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33
33
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- 1,2,10順番に
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34
34
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35
35
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```SQL
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36
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-
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37
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-
select * from tbl where find_in_set('1',text);
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38
36
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39
37
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select * from tbl where text regexp('(^|,)1(,|$)');
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40
38
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3
tuiki
test
CHANGED
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@@ -57,3 +57,79 @@
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57
57
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select * from tbl where find_in_set('10',text);
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58
58
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59
59
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```
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60
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+
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61
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+
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62
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+
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63
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+
# 効率的なデータの持ち方
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64
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+
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65
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+
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66
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+
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67
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+
ちゃんと正規化するならこうですね
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68
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+
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69
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+
- 元データ
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70
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+
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71
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+
```SQL
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72
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+
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73
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+
create table id_text(pid int primary key,id int,text int,unique(id,text));
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74
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+
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75
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+
insert into id_text values
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76
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+
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77
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+
(1,1,1),
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78
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+
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79
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+
(2,2,1),
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80
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+
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81
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+
(3,2,2),
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82
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+
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83
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+
(4,2,3),
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84
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+
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85
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+
(5,3,10),
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86
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+
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87
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+
(6,3,11),
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88
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+
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89
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+
(7,4,1),
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90
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+
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91
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+
(8,4,10),
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92
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+
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93
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+
(9,4,12),
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94
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+
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95
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+
(10,5,10),
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96
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+
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97
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+
(11,5,11),
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98
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+
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99
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+
(12,5,12),
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100
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+
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101
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+
(13,6,2),
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102
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+
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103
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+
(14,7,10),
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104
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+
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105
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+
(15,8,12);
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106
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+
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107
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+
```
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108
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+
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109
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+
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110
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+
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111
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+
- 全データ表示
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112
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+
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113
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+
```SQL
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114
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+
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115
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+
select id,group_concat(text) as text from id_text
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116
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+
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117
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+
group by id;
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118
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+
|
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119
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+
```
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120
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+
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121
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+
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122
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+
|
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123
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+
- 抽出
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124
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+
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125
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+
text=1を含むデータの抽出
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|
126
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+
|
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127
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+
```SQL
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128
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+
|
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129
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+
select id,group_concat(text) as text from id_text as t1
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130
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+
|
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131
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+
where exists(select 1 from id_text where text=1 and id=t1.id)
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132
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+
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133
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+
group by id;
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134
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+
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135
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+
```
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2
調整
test
CHANGED
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@@ -1,4 +1,4 @@
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1
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-
正規表現ですから先頭か,から始まり、その数字、,か末尾で終わる
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1
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+
正規表現ですから「先頭か,から始まり、その数字、,か末尾で終わる」
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2
2
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3
3
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と書きます。
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4
4
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1
調整
test
CHANGED
|
@@ -30,7 +30,7 @@
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30
30
|
|
|
31
31
|
|
|
32
32
|
|
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33
|
-
-1,2,10順番に
|
|
33
|
+
- 1,2,10順番に
|
|
34
34
|
|
|
35
35
|
```SQL
|
|
36
36
|
|