2

viewTotal添付の画像は結果セットを示しています。以下にコードを残します-各セル内の列全体の合計を計算できないのはなぜですか？viewTotal列の下の各セルに読み取りを依頼します4。

どの列をグループ化する必要があるかに関して、Web上で具体的なことは何も見つかりませんが、これはある種のグループ化の問題だと思います。3行すべてを残すことが重要です。1行だけを返したくありません。おそらく、この基準は私がやろうとしていることをより難しくしますか？

ありがとう、エヴァン

結果のプレビュー

Select topic_id, topic_subject, SUM(topicViews) as viewTotal, replyCount From
                        (
                        Select 
                            T.topic_id, T.topic_subject, Count(distinct Tvt.id) as topicViews, Count(Distinct R.reply_id) as replyCount, R.reply_id, R.reply_topic
                            From topic T                                                                         
                            LEFT JOIN topic_view_tracker Tvt ON
                                T.topic_id = Tvt.topic_id   
                            LEFT Join reply R ON
                                T.topic_id = R.reply_topic
                            Where   
                            T.topic_by = 10
                            Group By T.topic_id) B
                        Group By topic_id
                        Order by replyCount DESC

サンプルレコード：

トピックテーブル

╔══════════╦════════════════════════════╦══════════╗
║ TOPIC_ID ║       TOPIC_SUBJECT        ║ TOPIC_BY ║
╠══════════╬════════════════════════════╬══════════╣
║       25 ║ School police in the night ║       10 ║
║       29 ║ The first topic, enjoy it  ║       10 ║
║       30 ║ This is a normal title...  ║       10 ║
╚══════════╩════════════════════════════╩══════════╝

TOPIC_VIEW_TRACKERテーブル

╔════╦════════════╦══════════╗
║ ID ║  USER_IP   ║ TOPIC_ID ║
╠════╬════════════╬══════════╣
║  1 ║ xx.xx.xx.x ║       25 ║
║  2 ║ xx.xx.xx.x ║       25 ║
║  3 ║ xx.xxx.xxx ║       29 ║
║  4 ║ xxx.xx.xx  ║       30 ║
╚════╩════════════╩══════════╝

返信テーブル

╔══════════╦═════════════╗
║ REPLY_ID ║ REPLY_TOPIC ║
╠══════════╬═════════════╣
║        1 ║          25 ║
║        2 ║          29 ║
╚══════════╩═════════════╝

期待される出力（例）：

topic_idトピックサブジェクトビュー合計返信数
29最初のトピック、楽しんでください4 5
夜の25校の警察44
30これはトピックの通常のタイトルです...40
4

2 に答える 2

1 
SELECT  x.*, 
        COALESCE(y.viewTotal, 0) viewTotal,
        COALESCE(z.replyCount, 0) replyCount
FROM    topic x
        LEFT JOIN
        (
            SELECT  a.topic_by, COUNT(b.topic_ID) viewTotal
            FROM    topic a
                    LEFT JOIN topic_view_tracker b
                        ON a.topic_ID = b.topic_ID
            GROUP   BY a.topic_by
        ) y ON x.topic_by = y.topic_by
        LEFT JOIN
        (
            SELECT  reply_topic, COUNT(*) replyCount
            FROM    reply
            GROUP   BY reply_topic
        ) z ON  x.topic_ID = z.reply_topic
WHERE   x.topic_by = 10

OUTPUT (提供された記録に基づく)

╔══════════╦════════════════════════════╦══════════╦═══════════╦════════════╗
║ TOPIC_ID ║       TOPIC_SUBJECT        ║ TOPIC_BY ║ VIEWTOTAL ║ REPLYCOUNT ║
╠══════════╬════════════════════════════╬══════════╬═══════════╬════════════╣
║       25 ║ School police in the night ║       10 ║         4 ║          1 ║
║       29 ║ The first topic, enjoy it  ║       10 ║         4 ║          1 ║
║       30 ║ This is a normal title...  ║       10 ║         4 ║          0 ║
╚══════════╩════════════════════════════╩══════════╩═══════════╩════════════╝
于 2013-03-14T01:58:42.277 に答える
0

各行で合計ビューを繰り返す必要がある場合は、これを使用する必要があります。

Select topic_id, topic_subject, (SELECT Count(distinct id) FROM topic_view_tracker WHERE topic_id = B.topic_id)) AS viewTotal, replyCount From
                        (
                        Select 
                            T.topic_id, T.topic_subject, Count(distinct Tvt.id) as topicViews, Count(Distinct R.reply_id) as replyCount, R.reply_id, R.reply_topic
                            From topic T                                                                         
                            LEFT JOIN topic_view_tracker Tvt ON
                                T.topic_id = Tvt.topic_id   
                            LEFT Join reply R ON
                                T.topic_id = R.reply_topic
                            Where   
                            T.topic_by = 10
                            Group By T.topic_id) B
                        Group By topic_id
                        Order by replyCount DESC

しかし、正直なところ、これの理由はわかりません。簡単にSELECT Count(distinct id) FROM topic_view_tracker WHERE topic_id = 10個別に実行してから、残りのクエリを実行して、topic_view_tracker完全に省略できます

于 2013-03-14T01:43:53.767 に答える