回答編集履歴
1
chousei
test
CHANGED
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@@ -18,8 +18,30 @@
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18
18
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(2,2001,1),
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21
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-
(3,2002,
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21
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(3,2002,2),
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(4,2003,3),
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23
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-
(
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25
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(5,2004,null);
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```
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28
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+
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29
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として
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30
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```SQL
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32
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33
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delete from parent_tbl where pid=3;
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34
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35
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```
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36
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とするとchild_tblのcid=4のpidがnullになります
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また
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```SQL
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42
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update parent_tbl set pid=5 where pid=2;
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```
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とするとchild_tblのcid=3のpidが5になります
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