1

私はlinq to sqlの初心者です。内部結合内の選択の構文は何ですか?

 inner join ( select CCL_TMA_ID as SecurityIdMax ,
                                max(CCL_DATE) as DateMax
                         from   dbo.usrCOURSCLOTURE
                         where  CCL_DONNEE is not null
                                and CCL_DATE <= @d
                         group by CCL_TMA_ID
                       )

完全なクエリ:

 declare @d datetime
 select @d = getdate()

 select t0.CCL_TMA_ID as SecurityId ,
        t0.CCL_DATE as Date ,
        t0.CCL_DONNEE as Price ,
        t1.CCL_DONNEE as CurrencyPrice
 from   dbo.usrCOURSCLOTURE as t0
        inner join dbo.usrCOURSCLOTURE as t1 on t0.CCL_DEV_DONNEE = t1.CCL_TMA_ID
                                                and t0.CCL_DATE = t1.CCL_DATE
                                                and t1.CCL_DONNEE is not null

        inner join ( select CCL_TMA_ID as SecurityIdMax ,
                            max(CCL_DATE) as DateMax
                     from   dbo.usrCOURSCLOTURE
                     where  CCL_DONNEE is not null
                            and CCL_DATE <= @d
                     group by CCL_TMA_ID
                   ) cMax on t0.CCL_TMA_ID = SecurityIdMax
                             and t0.CCL_DATE <= DateMax
                             and t0.CCL_DATE >= DateMax-10
where t0.CCL_DATE > dateadd(year,-1,@d)
4

2 に答える 2

2

機能のいくつかを説明するいくつかのコメントを添えて、以下のクエリを実行しました。次のような <= に基づく複数条件の結合はできないことに注意してください。

on t0.CCL_TMA_ID = SecurityIdMax
                             and t0.CCL_DATE <= DateMax
                             and t0.CCL_DATE >= DateMax-10

最初の条件で参加し、その後 where でそれらを除外する必要があります

例えば

Datetime d = Datetime.Now;
Datetime lastYear = d.AddYears(-1);
var q = from t0 in db.usrCOURSCLOTURE
        join t1 in db.usrCOURSCLOTURE.where(z => z.CCL_DONNEE.HasValue) 
        on new {a = t0.CCL_DEV_DONNEE, b = t0.CCL_DATE} equals new {a = t1.CCL_TMA_ID, b = t1.CCL_DATE}
            // the above is how to do a join on multiple conditions
        join t2 in (
            from x0 in db.usrCOURSCLOTURE.where(z => z.CCL_DONNEE.HasValue && z.CCL_DATE < d)
            .GroupBy(z => z.CCL_TMA_ID)
            select new {SecurityIdMax = x0.Key, DateMax = x0.Max(z => z.CCL_DATE)}
            //this is how you get your groupby subquery
        )
        on t0.CCL_TMA_ID equals t2.SecurityIdMax
        where
          t0.CCL_DATE  > lastYear
          && t0.CCL_DATE <= t2.DateMax
          && t0.CCL_DATE >= SqlFunctions.DateAdd("DAY", -10, t2.DateMax) //nb not sure on the interval - correct this!
        select new {SecurityId = t0.CCL_TMA_ID,
                    Date = t0.CCL_DATE,
                    Price = t0.CCL_DONNEE,
                    CurrencyPrice = t1.CCL_DONNEE};

また、「SqlFunctions」クラスは、System.Data.Entity アセンブリの名前空間 System.Data.Objects.SqlClient にあることに注意してください。

于 2013-11-05T11:00:44.563 に答える
0

ステートメントを括弧で囲むことにより、データのサブセットを作成します。この場合、列dbo.usrCOURSCLOTUREごとにグループ化されたものから選択されCCL_TMA_IDます。

より明確にするために、別の方法で言いましょう。

   @subsetOfData = select CCL_TMA_ID as SecurityIdMax, max(CCL_DATE) as DateMax
                      from   dbo.usrCOURSCLOTURE
                     where  CCL_DONNEE is not null and CCL_DATE <= @d
                  group by CCL_TMA_ID

その後

select t0.CCL_TMA_ID as SecurityId ,
        t0.CCL_DATE as Date ,
        t0.CCL_DONNEE as Price ,
        t1.CCL_DONNEE as CurrencyPrice
 from   dbo.usrCOURSCLOTURE as t0
        inner join dbo.usrCOURSCLOTURE as t1 on t0.CCL_DEV_DONNEE = t1.CCL_TMA_ID
                                                and t0.CCL_DATE = t1.CCL_DATE
                                                and t1.CCL_DONNEE is not null

        inner join @subsetOfData as cMax on t0.CCL_TMA_ID = SecurityIdMax
                             and t0.CCL_DATE <= DateMax
                             and t0.CCL_DATE >= DateMax-10
where t0.CCL_DATE > dateadd(year,-1,@d)
于 2013-11-05T10:46:50.423 に答える