2

次のテーブルがあります-

Search Result
----------------
SearchResultID PK
ProductID FK
SearchQuery
WebsiteName
URL
IsFound
CreatedOn
BatchID
Name

SearchResultItem
-----------------
SearchResultItemID PK
SearchResultID FK
Name
Value

これらのテーブルは 1 対多の関係にあるため、1 つの検索結果に複数の検索結果アイテムが含まれることがあります。

これらのテーブルで INNER JOIN を実行できますが、明らかに、検索結果アイテムごとに 1 つの行が得られます。理想的には、検索結果ごとに1行が必要です。たとえば...

SearchResultID | ProductID | SearchQuery | WebsiteName | URL | IsFound | 
CreatedOn | BatchID | Name | SearchResultItemID | Name 1 | Value 1 | Name 2 | 
Value 2 | Name 3 | Value 3 |

これは可能ですか？もしそうなら、誰かが私がこれを行う方法について正しい方向に私を向けることができます-ms-sqlでのみ、このようなものになると思います-単一行への1対多のSQL選択-mysql

4

1 に答える 1

4

ROW_NUMBER()関数を使用して、各検索結果アイテムに各検索結果内のランクを与えることができます。

SELECT  SearchResultItemID,
        SearchResultID,
        Name,
        Value,
        RowNumber = ROW_NUMBER() OVER(PARTITION BY SearchResultID ORDER BY SearchresultItemID)
FROM    SearchResultItem;

アイテムの数がわかっている場合は、集計関数を使用して各名前/値のペアを取得できます。

WITH RankedItem AS
(   SELECT  SearchResultItemID,
            SearchResultID,
            Name,
            Value,
            RowNumber = ROW_NUMBER() OVER(PARTITION BY SearchResultID ORDER BY SearchresultItemID)
    FROM    SearchResultItem
)
SELECT  SearchResultID,
        Name1 = MIN(CASE WHEN RowNumber = 1 THEN Name END),
        Value1 = MIN(CASE WHEN RowNumber = 1 then Value END),
        Name2 = MIN(CASE WHEN RowNumber = 2 THEN Name END),
        Value2 = MIN(CASE WHEN RowNumber = 2 then Value END),
        Name3 = MIN(CASE WHEN RowNumber = 3 THEN Name END),
        Value3 = MIN(CASE WHEN RowNumber = 3 then Value END),
        Name4 = MIN(CASE WHEN RowNumber = 4 THEN Name END),
        Value5 = MIN(CASE WHEN RowNumber = 4 then Value END)
FROM    RankedItem
GROUP BY SearchResultID;

次に、これを検索結果テーブルに結合して、完全なクエリを提供できます。

WITH RankedItem AS
(   SELECT  SearchResultItemID,
            SearchResultID,
            Name,
            Value,
            RowNumber = ROW_NUMBER() OVER(PARTITION BY SearchResultID ORDER BY SearchresultItemID)
    FROM    SearchResultItem
), Items AS
(   SELECT  SearchResultID,
            Name1 = MIN(CASE WHEN RowNumber = 1 THEN Name END),
            Value1 = MIN(CASE WHEN RowNumber = 1 then Value END),
            Name2 = MIN(CASE WHEN RowNumber = 2 THEN Name END),
            Value2 = MIN(CASE WHEN RowNumber = 2 then Value END),
            Name3 = MIN(CASE WHEN RowNumber = 3 THEN Name END),
            Value3 = MIN(CASE WHEN RowNumber = 3 then Value END),
            Name4 = MIN(CASE WHEN RowNumber = 4 THEN Name END),
            Value4 = MIN(CASE WHEN RowNumber = 4 then Value END)
    FROM    RankedItem
    GROUP BY SearchResultID
)

SELECT  SearchResult.SearchResultID,
        SearchResult.ProductID,
        SearchResult.SearchQuery,
        SearchResult.WebsiteName,
        SearchResult.URL,
        SearchResult.IsFound,
        SearchResult.CreatedOn,
        SearchResult.BatchID,
        SearchResult.Name,
        Items.Name1,
        Items.Value1,
        Items.Name2,
        Items.Value2,
        Items.Name3,
        Items.Value3,
        Items.Name4,
        Items.Value4
FROM    SearchResult
        INNER JOIN Items
            ON SearchResult.SearchResultID = Items.SearchResultID;

SQL Fiddle の例

可変数の値を返したい場合は、動的 SQL を使用する必要があります。

DECLARE @SQL NVARCHAR(MAX) = '';

SELECT  @SQL = @SQL + ',[Name' + rn + '], [Value' + rn + '] '
FROM    (   SELECT  DISTINCT
                    rn = CAST(ROW_NUMBER() OVER(PARTITION BY SearchResultID ORDER BY SearchresultItemID) AS VARCHAR)
            FROM    SearchResultItem
        ) p;

SET @SQL = 'WITH RankedItem AS
            (   SELECT  SearchResultItemID,
                        SearchResultID,
                        Name,
                        Value,
                        RowNumber = ROW_NUMBER() OVER(PARTITION BY SearchResultID ORDER BY SearchresultItemID)
                FROM    SearchResultItem
            ), UnPivoted AS
            (   SELECT  upvt.SearchResultID,
                        Name = upvt.n + CAST(RowNumber AS VARCHAR),
                        upvt.v
                FROM    RankedItem
                        UNPIVOT
                        (   n
                            FOR v IN ([Name], [Value])
                        ) upvt
            ), Pivoted AS
            (   SELECT  *
                FROM    UnPivoted
                        PIVOT
                        (   MAX(V)
                            FOR Name IN (' + STUFF(@SQL, 1, 1, '') + ')
                        ) pvt
            )
            SELECT  SearchResult.SearchResultID,
                    SearchResult.ProductID,
                    SearchResult.SearchQuery,
                    SearchResult.WebsiteName,
                    SearchResult.URL,
                    SearchResult.IsFound,
                    SearchResult.CreatedOn,
                    SearchResult.BatchID,
                    SearchResult.Name' + @SQL + '                       
            FROM    SearchResult
                    INNER JOIN Pivoted
                        ON SearchResult.SearchResultID = Pivoted.SearchResultID;';

EXECUTE SP_EXECUTESQL @SQL;

SQL Fiddle の例

注意:行を結合した結果を達成する方法が複数あることを示すために、動的SQLでこれを行う別の方法を意図的に使用しました。

于 2013-05-31T11:08:52.403 に答える