SQL の作成時に二重にサブクエリを生成する LinqToEntities クエリがあります。これにより、クエリが実行されるたびに結果セットに 0 ~ 3 個の結果が返されます。サブクエリ自体は、単一のランダムな結果を生成します (そうあるべきです)。ここで何が起こっているのですか?
LINQ クエリ:
from jpj in JobProviderJobs
where jpj.JobID == 4725
&& jpj.JobProviderID == (from jp2 in JobProviderJobs
where jp2.JobID == 4725
orderby Guid.NewGuid()
select jp2.JobProviderID).FirstOrDefault()
select new
{
JobProviderID = jpj.JobProviderID
}
次の SQL を生成します。
SELECT
[Filter2].[JobID] AS [JobID],
[Filter2].[JobProviderID1] AS [JobProviderID]
FROM (SELECT [Extent1].[JobID] AS [JobID], [Extent1].[JobProviderID] AS [JobProviderID1], [Limit1].[JobProviderID] AS [JobProviderID2]
FROM [dbo].[JobProviderJob] AS [Extent1]
LEFT OUTER JOIN (SELECT TOP (1) [Project1].[JobProviderID] AS [JobProviderID]
FROM ( SELECT
NEWID() AS [C1],
[Extent2].[JobProviderID] AS [JobProviderID]
FROM [dbo].[JobProviderJob] AS [Extent2]
WHERE 4725 = [Extent2].[JobID]
) AS [Project1]
ORDER BY [Project1].[C1] ASC ) AS [Limit1] ON 1 = 1
WHERE 4725 = [Extent1].[JobID] ) AS [Filter2]
LEFT OUTER JOIN (SELECT TOP (1) [Project2].[JobProviderID] AS [JobProviderID]
FROM ( SELECT
NEWID() AS [C1],
[Extent3].[JobProviderID] AS [JobProviderID]
FROM [dbo].[JobProviderJob] AS [Extent3]
WHERE 4725 = [Extent3].[JobID]
) AS [Project2]
ORDER BY [Project2].[C1] ASC ) AS [Limit2] ON 1 = 1
WHERE [Filter2].[JobProviderID1] = (CASE WHEN ([Filter2].[JobProviderID2] IS NULL) THEN 0 ELSE [Limit2].[JobProviderID] END)
編集:
したがって、サブクエリをこれに変更するとうまくいきますが、その理由はわかりません
(from jp2 in JobProviderJobs
where jp2.JobID == 4725
orderby Guid.NewGuid()
select jp2).FirstOrDefault().JobProviderID