回答編集履歴
5
追記
test
CHANGED
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@@ -127,3 +127,5 @@
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127
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)
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```
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+
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ただ、unionしないと駄目な時点で、正規化からは外れています。
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4
追記
test
CHANGED
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@@ -65,3 +65,65 @@
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65
65
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66
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[MySQL 5.7で生成カラムを使ってCHECK制約もどきを実装する](https://qiita.com/hmatsu47/items/ddf0fc74f2dc3bb7556f)
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追記
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--
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「友達かも」リストについては、事象を分けて考えれば、そんなに難しい事ではありません
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```SQL
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select * from user
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where userid in (
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82
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select followingid from follow
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where userid in ( -- 友達が承認された友達
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select followingid from follow where status=1 and userid=1 -- 承認された友達
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88
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+
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union all
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90
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91
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select userid from follow where status=1 and followingid=1 -- 承認した友達
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92
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)
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and status = 1
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96
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union all
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select userid from follow
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where followingid in ( -- 友達が承認した友達
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select followingid from follow where status=1 and userid=1 -- 承認された友達
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union all
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select userid from follow where status=1 and followingid=1 -- 承認した友達
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)
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and status = 1
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)
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and userid NOT IN(1) -- 起点のユーザー
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and userid not in ( -- 友達
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select followingid from follow where status=1 and userid=1 -- 承認された友達
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122
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union all
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select userid from follow where status=1 and followingid=1 -- 承認した友達
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)
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128
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```
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3
修正
test
CHANGED
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@@ -14,15 +14,15 @@
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14
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where userid in (
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-
select following from follow
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select followingid from follow
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where userid in (--友達が承認された友達
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where userid in ( -- 友達が承認された友達
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-
select following from follow where status=1 and userid=1 -- 承認された友達
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select followingid from follow where status=1 and userid=1 -- 承認された友達
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union all
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select userid from follow where status=1 and following=1 -- 承認した友達
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select userid from follow where status=1 and followingid=1 -- 承認した友達
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)
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@@ -32,13 +32,15 @@
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select userid from follow
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-
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+
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where followingid in ( -- 友達が承認した友達
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-
select following from follow where status=1 and userid=1 -- 承認された友達
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select followingid from follow where status=1 and userid=1 -- 承認された友達
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union all
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select userid from follow where status=1 and following=1 -- 承認した友達
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select userid from follow where status=1 and followingid=1 -- 承認した友達
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)
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@@ -46,11 +48,11 @@
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46
48
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union all
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48
50
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49
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select following from follow where status=1 and userid=1 -- 承認された友達
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51
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select followingid from follow where status=1 and userid=1 -- 承認された友達
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50
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union all
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53
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-
select userid from follow where status=1 and following=1 -- 承認した友達
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55
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select userid from follow where status=1 and followingid=1 -- 承認した友達
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)
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2
修正
test
CHANGED
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@@ -44,11 +44,17 @@
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44
44
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45
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and status = 1
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46
46
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47
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union all
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48
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49
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select following from follow where status=1 and userid=1 -- 承認された友達
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50
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union all
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52
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53
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select userid from follow where status=1 and following=1 -- 承認した友達
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47
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)
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48
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and userid NOT IN(1)
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-
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-
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```
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54
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1
追記
test
CHANGED
|
@@ -53,3 +53,7 @@
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53
53
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```
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54
54
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3.この構造で逆の組み合わせの一意制約は無理ですね、
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59
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+
[MySQL 5.7で生成カラムを使ってCHECK制約もどきを実装する](https://qiita.com/hmatsu47/items/ddf0fc74f2dc3bb7556f)
|