-1

これは、MSSQL を MySql に変換した結果です。以下は、私が仕事をしようとしているコードです:

CREATE TEMPORARY TABLE PageIndex (
  IndexId int AUTO_INCREMENT NOT NULL PRIMARY KEY,
  ItemId VARCHAR(64)
);

INSERT INTO PageIndex (ItemId)
SELECT Paths.PathId
  FROM Paths,
       ((SELECT Paths.PathId
           FROM AllUsers, Paths
          WHERE Paths.ApplicationId = @ApplicationId
            AND AllUsers.PathId = Paths.PathId
            AND (@Path IS NULL
                OR Paths.LoweredPath LIKE LOWER(@Path))) AS SharedDataPerPath
          UNION -- This used to be a FULL OUTER JOIN but MySQL doesnt support that.
        (SELECT DISTINCT Paths.PathId
           FROM PerUser, Paths
          WHERE Paths.ApplicationId = @ApplicationId
            AND PerUser.PathId = Paths.PathId
            AND (@Path IS NULL
                OR Paths.LoweredPath LIKE LOWER(@Path))) AS UserDataPerPath
             ON SharedDataPerPath.PathId = UserDataPerPath.PathId)
          WHERE Paths.PathId = SharedDataPerPath.PathId OR Paths.PathId = UserDataPerPath.PathId
          ORDER BY Paths.Path ASC;

変数が既に存在すると仮定します。これが壊れているのは「As SharedDataPerPath」の部分なので、テーブルが MySQL でサポートされていないようにアクセスできるように、select ステートメントにエイリアスを設定していると思いますか? テーブル スキーマが役立つ場合は、コメントで返信してください。それを質問に追加します。

前もって感謝します！

4

3 に答える 3

1

左右の外部結合を結合した上記の方法はうまく機能し、一般的に受け入れられている解決策のようです。ただし、メッセージボード全体でさまざまな例を読んだときに見つけたように、これにはいくつかの詳細が残されています。

  1. 結合に使用する列のテーブルソースを1つの選択から別の選択に交換して、外部結合によって生成されたNULLを考慮します。

  2. COALESCE関数を「固定列」に追加します。これは、外部結合によって生成されたNULLとして返される場合もあります。

例：

SELECT
`Wins_VW`.`Year`,
`Wins_VW`.`Period`,
COALESCE(`Wins_VW`.`Wins`,0) as Wins,
COALESCE(`Leads_VW`.`Leads`,0) as Leads
FROM `Wins_VW` LEFT OUTER JOIN `Leads_VW`
ON( `Wins_VW`.`Year` = `Leads_VW`.`Year`
AND `Wins_VW`.`Period` = `Leads_VW`.`Period`)

UNION

SELECT
`Leads_VW`.`Year`,
`Leads_VW`.`Period`,
COALESCE(`Wins_VW`.`Wins`,0) as Wins,
COALESCE(`Leads_VW`.`Leads`,0) as Leads
FROM `Wins_VW` RIGHT OUTER JOIN `Leads_VW`
ON( `Wins_VW`.`Year` = `Leads_VW`.`Year`
AND `Wins_VW`.`Period` = `Leads_VW`.`Period`)
于 2012-07-17T20:51:07.803 に答える
1 
-- Assuming these are defined in your store procedure
DECLARE @ApplicationId VARCHAR(64);
DECLARE @Path VARCHAR(256);
SET @ApplicationId = NULL;
Set @Path = NULL;

CREATE TEMPORARY TABLE SharedDataPerPath
(
  PathId VARCHAR(256)
);

CREATE TABLE UserDataPerPath
(
  PathId VARCHAR(256)
);

-- Do this instead of aliasing a select statment 'AS SharedDataPerPath'
INSERT INTO SharedDataPerPath
SELECT Paths.PathId
  FROM aspnet_PersonalizationAllUsers AllUsers, aspnet_Paths Paths
 WHERE Paths.ApplicationId = @ApplicationId
   AND AllUsers.PathId = Paths.PathId
   AND (@Path IS NULL OR Paths.LoweredPath LIKE LOWER(@Path));

-- Do this instead of aliasing a select statement 'AS UserDataPerPath'
INSERT INTO UserDataPerPath
SELECT DISTINCT Paths.PathId
  FROM aspnet_PersonalizationPerUser PerUser, aspnet_Paths Paths
 WHERE Paths.ApplicationId = @ApplicationId
   AND PerUser.PathId = Paths.PathId
   AND (@Path IS NULL OR Paths.LoweredPath LIKE LOWER(@Path));

-- This is how I would do my 'FULL OUTER JOIN'
SELECT Paths.PathId
    FROM `wppi_net_db`.`aspnet_Paths` Paths,
         (SELECT *
            FROM SharedDataPerPath AS s
            LEFT OUTER JOIN UserDataPerPath AS u
              ON s.PathID = u.PathID
           UNION -- OR UNION ALL see: http://www.xaprb.com/blog/2006/05/26/how-to-write-full-outer-join-in-mysql/
          SELECT *
            FROM SharedDataPerPath AS s
           RIGHT OUTER JOIN UserDataPerPath AS u
              ON s.PathID = u.PathID) AS DataPerPaths
   WHERE Paths.PathId = DataPerPaths.PathId
   ORDER BY Paths.Path ASC;

-- At some point you need to drop your temp tables
DROP TEMPORARY TABLE SharedDataPerPath;
DROP TEMPORARY TABLE UserDataPerPath;
于 2011-01-24T04:19:18.800 に答える