0

これは、実行速度が非常に遅い MS Access クエリです。Resultsテーブルがメイン テーブルで、、P、BおよびSテーブルCが子テーブルです。列の組み合わせはIndex、ResultIDこれらすべてのテーブルで一意です。Cしたがって、たとえば、テーブルにIndexは「1」と2の行が 1 つしか存在できませResultIDん。私は JOIN を使用していません。なぜなら、MS Access は内部結合しかサポートしていないためです。Results他のテーブルに対応するレコードがない場合でも、テーブル内のすべてのレコード。

SELECT 
    [Results].[Id],
    [Results].[Name],
    [Results].[OfferPrice],
    [Results].[RegPrice],
    [Results].[ImageFileName],
    [Results].[Image],
    [Results].[URL],
    (SELECT P.P FROM P WHERE P.ResultID = Results.Id AND P.Index = "0") as P0,
    (SELECT P.P FROM P WHERE P.ResultID = Results.Id AND P.Index = "1") as P1,
    (SELECT P.P FROM P WHERE P.ResultID = Results.Id AND P.Index = "2") as P2,
    (SELECT P.P FROM P WHERE P.ResultID = Results.Id AND P.Index = "3") as P3,
    (SELECT P.P FROM P WHERE P.ResultID = Results.Id AND P.Index = "4") as P4,
    (SELECT P.P FROM P WHERE P.ResultID = Results.Id AND P.Index = "5") as P5,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "0") as B0,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "1") as B1,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "2") as B2,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "3") as B3,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "4") as B4,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "5") as B5,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "6") as B6,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "7") as B7,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "8") as B8,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "9") as B9,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "10") as B10,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "11") as B11,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "12") as B12,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "13") as B13,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "14") as B14,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "15") as B15,
    (SELECT B.B FROM B WHERE B.ResultID = Results.Id AND B.Index = "16") as B16,
    (SELECT S.S FROM S WHERE S.ResultID = Results.Id AND S.Index = "1") as S1,
    (SELECT S.S FROM S WHERE S.ResultID = Results.Id AND S.Index = "2") as S2,
    (SELECT S.S FROM S WHERE S.ResultID = Results.Id AND S.Index = "3") as S3,
    (SELECT S.S FROM S WHERE S.ResultID = Results.Id AND S.Index = "4") as S4,
    (SELECT S.S FROM S WHERE S.ResultID = Results.Id AND S.Index = "5") as S5,
    (SELECT S.S FROM S WHERE S.ResultID = Results.Id AND S.Index = "6") as S6,
    (SELECT S.S FROM S WHERE S.ResultID = Results.Id AND S.Index = "7") as S7,
    (SELECT S.S FROM S WHERE S.ResultID = Results.Id AND S.Index = "8") as S8,
    (SELECT S.S FROM S WHERE S.ResultID = Results.Id AND S.Index = "9") as S9,
    (SELECT S.S FROM S WHERE S.ResultID = Results.Id AND S.Index = "10") as S10,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "0") as C0,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "1") as C1,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "2") as C2,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "3") as C3,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "4") as C4,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "5") as C5,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "6") as C6,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "7") as C7,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "8") as C8,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "9") as C9,
    (SELECT C.C FROM C WHERE C.ResultID = Results.Id AND C.Index = "10") as C10
FROM 
    Results
4

3 に答える 3

4

次のものをどこで入手したかわかりません。

MS Accessは内部結合のみをサポートし、必要なのは外部結合であるため、JOINを使用していません。

MSAccessはOUTER JOIN構文をサポートしています。

LEFT JOIN相関するサブクエリを各テーブル間で置き換えることができます。コードは次のようになります。

SELECT 
    [Results].[Id],
    [Results].[Name],
    [Results].[OfferPrice],
    [Results].[RegPrice],
    [Results].[ImageFileName],
    [Results].[Image],
    [Results].[URL],
    max(IIF(P.Index = "0", P.P, null)) as P0,
    max(IIF(P.Index = "1", P.P, null)) as P1,
    max(IIF(P.Index = "2", P.P, null)) as P2,
    max(IIF(P.Index = "3", P.P, null)) as P3,
    max(IIF(P.Index = "4", P.P, null)) as P4,
    max(IIF(P.Index = "5", P.P, null)) as P5,
    max(IIF(B.Index = "0", B.B, null)) as B0,
    max(IIF(B.Index = "1", B.B, null)) as B1,
    max(IIF(B.Index = "8", B.B, null)) as B8,
    max(IIF(S.Index = "2", S.S, null)) as S2,
    max(IIF(C.Index = "1", C.C, null)) as C1
FROM Results
LEFT JOIN P
    on P.ResultID = Results.Id
LEFT JOIN B
    on B.ResultID = Results.Id
LEFT JOIN S
    on S.ResultID = Results.Id
LEFT JOIN C
    on C.ResultID = Results.Id
GROUP BY [Results].[Id],
    [Results].[Name],
    [Results].[OfferPrice],
    [Results].[RegPrice],
    [Results].[ImageFileName],
    [Results].[Image],
    [Results].[URL]

関数を使用してデータをピボットすることもできるはずですTRANSFORM。コードは次のようになります。

TRANSFORM Max(Src.Value)
select 
    [Results].[Id],
    [Results].[Name],
    [Results].[OfferPrice],
    [Results].[RegPrice],
    [Results].[ImageFileName],
    [Results].[Image],
    [Results].[URL]
from results as R
left join
(
    select ResultID, P as Value, "P"&Index as col
    from p
    union all
    select ResultID, B as Value, "B"&Index as col
    from B
    union all
    select ResultID, C as Value, "C"&Index as col
    from C
    union all
    select ResultID, S as Value, "S"&Index as col
    from S
) as Src
    on R.id = Src.ResultID
GROUP BY [Results].[Id], [Results].[Name],
    [Results].[OfferPrice],[Results].[RegPrice],
    [Results].[ImageFileName], [Results].[Image],
    [Results].[URL]
PIVOT Src.col
于 2013-02-12T16:27:16.013 に答える
1

これはかなり速く実行されるはずです。1 つのテーブルと複数のテーブルの結合の間の結合でピボットを実行しようとしているようです。以下のunionizedテーブルは、すべての結合を置き換えます。そして、これがピボットされているという事実により、相関するサブクエリを実行する必要がなくなります。

TRANSFORM Max(unionized.DataColumn) AS MaxOfDataColumn
SELECT Results.ResName, Results.OfferPrice, Results.RegPrice, Results.Image, Results.URL
FROM (
    Select B.ID, B.B as DataColumn, "B"&B.B as tableName from B
    union all select C.ID, C.C, "C"&C.C from C
    union all select P.ID, P.P, "P"&P.P from P
    union all select S.ID, S.S, "S"&S.S from S)  AS unionized 
RIGHT JOIN Results ON unionized.ID = Results.ID
GROUP BY Results.ResName, Results.OfferPrice, Results.RegPrice, Results.Image, Results.URL
PIVOT unionized.tableName;

サンプル列を使用していると想定しているため、少しクリーンアップする必要がありますが、うまくいけばアイデアが得られます。

于 2013-02-12T16:39:54.750 に答える
1

結合を明示的にすると、クエリの実行が速くなります。テンプレートは次のとおりです。

SELECT 
    [Results].[Id],
    [Results].[Name],
    [Results].[OfferPrice],
    [Results].[RegPrice],
    [Results].[ImageFileName],
    [Results].[Image],
    [Results].[URL],
    max(iif(p.index = "0", p.p, "")) as p0,
    . . .
FROM results left outer join
     p
     on results.id = p.resultid left outer join
     . . .
group by [Results].[Id],
    [Results].[Name],
    [Results].[OfferPrice],
    [Results].[RegPrice],
    [Results].[ImageFileName],
    [Results].[Image],
    [Results].[URL]

left outer joinを使用してテーブルを取り込み、正しい条件でそれらを結合し、集計を使用して結果ごとに 1 行に縮小するという考え方です。のロジックは、SELECT設定したロジックに従って値を選択します。

于 2013-02-12T16:25:29.063 に答える