回答編集履歴
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追記
answer
CHANGED
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@@ -6,4 +6,38 @@
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6
6
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- ニックネームの重複回避をとるか
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7
7
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- 同じだったときにどちらかのIDが優先されるようなロジックを提示
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8
8
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9
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-
のどちらかが必要になります
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9
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+
のどちらかが必要になります
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10
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+
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11
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# 追記
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12
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+
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13
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ちなみにnickNameIDと優先順位が同じだったときはnoの小さいものを選ぶとこうです
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14
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+
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15
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- 元データ
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16
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```SQL
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17
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create table tbl(ID int primary key,nicknameID int,priority int);
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18
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insert into tbl values
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19
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(1,20,1),
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20
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(2,20,2),
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21
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(3,20,3),
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22
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(4,21,2),
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23
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(5,21,3),
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24
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(6,23,2),
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25
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(7,24,1),
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26
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(8,24,1),
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27
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(9,24,4),
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28
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(10,25,3),
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29
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(11,25,3),
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30
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(12,25,4),
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31
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(13,25,4),
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32
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(14,26,2),
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33
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(15,26,3),
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34
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(16,26,4),
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35
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(17,26,4),
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36
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(18,26,4);
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37
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```
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38
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39
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- 抽出
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40
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```SQL
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41
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select * from tbl as t1
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42
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where not exists(select 1 from tbl as t2 where t1.nicknameID=t2.nicknameID and (t1.priority>t2.priority or (t1.priority=t2.priority and t1.ID>t2.ID)))
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43
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```
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