回答編集履歴
3
調整
test
CHANGED
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@@ -74,9 +74,9 @@
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74
74
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75
75
|
WHERE id in(
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76
76
|
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77
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-
SELECT max(id) FROM `tbl_message_pre`
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77
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+
SELECT max(id) FROM `tbl_message_pre`
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78
78
|
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79
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-
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79
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+
WHERE board_id IN (SELECT id FROM `tbl_board` WHERE user_name_1='田中' OR user_name_2='田中')
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80
80
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81
81
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GROUP BY board_id
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82
82
|
|
2
typo
test
CHANGED
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@@ -70,9 +70,9 @@
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70
70
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71
71
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```SQL
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72
72
|
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73
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-
SELECT * FROM `tbl_message_pre`
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|
73
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+
SELECT * FROM `tbl_message_pre`
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74
74
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75
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-
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75
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+
WHERE id in(
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76
76
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77
77
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SELECT max(id) FROM `tbl_message_pre` WHERE 1
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78
78
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1
追記
test
CHANGED
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@@ -37,3 +37,55 @@
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37
37
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ORDER BY created_at DESC;
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38
38
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39
39
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```
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|
40
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+
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41
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+
# 検証
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|
42
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+
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43
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+
ざっと検証しました
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44
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+
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45
|
+
まず、田中を含むboard_idを取るのはこう
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|
46
|
+
|
|
47
|
+
```SQL
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|
48
|
+
|
|
49
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+
SELECT id FROM `tbl_board` WHERE user_name_1='田中' OR user_name_2='田中';
|
|
50
|
+
|
|
51
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+
```
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|
52
|
+
|
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53
|
+
該当するboard_id毎のmaxのメッセージidをとるのがこう
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|
54
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+
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55
|
+
```SQL
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|
56
|
+
|
|
57
|
+
SELECT board_id,max(id) FROM `tbl_message_pre`
|
|
58
|
+
|
|
59
|
+
WHERE board_id IN (SELECT id FROM `tbl_board` WHERE user_name_1='田中' OR user_name_2='田中')
|
|
60
|
+
|
|
61
|
+
GROUP BY board_id;
|
|
62
|
+
|
|
63
|
+
```
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|
64
|
+
|
|
65
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+
※ただし、実際のほしいのはmax(id)だけ
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|
66
|
+
|
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67
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+
|
|
68
|
+
|
|
69
|
+
maxのメッセージidから全データを抜き出してソートするのがこう
|
|
70
|
+
|
|
71
|
+
```SQL
|
|
72
|
+
|
|
73
|
+
SELECT * FROM `tbl_message_pre` WHERE 1
|
|
74
|
+
|
|
75
|
+
and id in(
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|
76
|
+
|
|
77
|
+
SELECT max(id) FROM `tbl_message_pre` WHERE 1
|
|
78
|
+
|
|
79
|
+
AND board_id IN (SELECT id FROM `tbl_board` WHERE user_name_1='田中' OR user_name_2='田中')
|
|
80
|
+
|
|
81
|
+
GROUP BY board_id
|
|
82
|
+
|
|
83
|
+
)
|
|
84
|
+
|
|
85
|
+
ORDER BY created_at DESC;
|
|
86
|
+
|
|
87
|
+
|
|
88
|
+
|
|
89
|
+
```
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|
90
|
+
|
|
91
|
+
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