回答編集履歴
2
補足
test
CHANGED
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@@ -4,11 +4,11 @@
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4
4
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5
5
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select 路線ID, 路線名
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6
6
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7
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-
, (select count(物件ID) from 物件
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7
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+
, coalesce((select count(物件ID) from 物件
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8
8
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9
9
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where 路線.路線ID in (路線1, 路線2, 路線3)
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10
10
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11
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-
) as 物件数
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11
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+
), 0) as 物件数
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12
12
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13
13
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from 路線
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14
14
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1
追記
test
CHANGED
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@@ -13,3 +13,17 @@
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13
13
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from 路線
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14
14
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15
15
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```
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16
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+
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17
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+
結合しての集計なら
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18
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+
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19
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+
```SQL
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20
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+
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21
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+
select 路線ID, 路線名, count(物件ID)
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22
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+
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23
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+
from 路線 left join 物件
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24
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+
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25
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+
on 路線.路線ID in (物件.路線1, 物件.路線2, 物件.路線3)
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26
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+
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27
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+
group by 路線ID, 路線名
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28
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+
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29
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+
```
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