回答編集履歴
1
sample
test
CHANGED
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@@ -3,3 +3,43 @@
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3
3
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- set @num=0;update set 該当カラム=(@num:=@num+1) order by なんちゃら、としてユニークにし
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4
4
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5
5
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- alter tableで当該カラムにuniqu属性をつける
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6
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+
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7
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8
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9
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# sample
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10
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11
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12
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13
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- 仮データ作成
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14
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15
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```SQL
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16
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+
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17
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create table tbl(val double);
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18
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19
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insert into tbl values(rand()),(rand()),(rand()),(rand()),(rand());
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20
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21
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```
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22
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23
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- カラム追加
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24
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25
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```SQL
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26
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27
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alter table tbl add id int not null first;
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28
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29
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```
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30
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31
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- uniqueなidを投入
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32
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33
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```SQL
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34
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35
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update tbl set id=(select @a:=@a+1 from (select @a:=0) as dummy) order by val;
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36
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37
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````
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38
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39
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- unique属性追加
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40
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41
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```SQL
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42
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43
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alter table tbl add unique(id);
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44
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45
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```
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