Question

安装.Net 4.5后，EF生成的查询出现问题。 linq中.Net 4.0的相同查询正常工作。我正在使用Firebird数据库，它不支持命令OUTER APPLY。有没有办法修改以下查询linq，以便它在.Net 4.5？

中运行

当前的linq查询：

int[] AROIds = (from x in context.RISK_T_ASSESS_HIST
               where (x.ID_RISKOBJECT.HasValue && x.F_CREATEDON >= Freq.StartDate 
               && x.F_CREATEDON <= Freq.EndDate)
               group x by x.ID_RISKOBJECT into gr
               let lastCreated = gr.Max(p => p.F_CREATEDON)
               select new
               {
                 ObjId = gr.Key
                 , LastStatus = gr.Where(p => p.F_CREATEDON == lastCreated 
                   && p.ID_RISKOBJECT == gr.Key)
                   .Select(p => p.F_STATUS).FirstOrDefault()
               }).Where(x => x.LastStatus == 0 || x.LastStatus == 1)
               .Select(x => x.ObjId.Value).ToArray();

生成的SQL。净4.5：

SELECT
"Project1"."ID_RISKOBJECT" AS "ID_RISKOBJECT"
FROM (SELECT
    "GroupBy1"."A1" AS "C1",
    "GroupBy1"."K1" AS "ID_RISKOBJECT"
    FROM ( SELECT
        "Extent1"."ID_RISKOBJECT" AS "K1",
        MAX("Extent1"."F_CREATEDON") AS "A1"
        FROM "RISK_T_ASSESS_HIST" AS "Extent1"
        WHERE (("Extent1"."ID_RISKOBJECT" IS NOT NULL)
        AND ("Extent1"."F_CREATEDON" >= 2013-04-17))
        AND ("Extent1"."F_CREATEDON" <= 2013-04-17)
        GROUP BY "Extent1"."ID_RISKOBJECT"
    ) AS "GroupBy1" ) AS "Project1"
OUTER APPLY (SELECT FIRST (1)
    "Extent2"."F_STATUS" AS "F_STATUS"
    FROM "RISK_T_ASSESS_HIST" AS "Extent2"
    WHERE (((("Extent2"."ID_RISKOBJECT" IS NOT NULL)
    AND ("Extent2"."F_CREATEDON" >= 2013-04-17))
    AND ("Extent2"."F_CREATEDON" <= @2013-04-17))
    AND (("Project1"."ID_RISKOBJECT" = "Extent2"."ID_RISKOBJECT") OR (("Project1"."ID_RISKOBJECT" IS NULL)
    AND ("Extent2"."ID_RISKOBJECT" IS NULL)))) AND (("Extent2"."F_CREATEDON" = "Project1"."C1")
    AND ("Extent2"."ID_RISKOBJECT" = "Project1"."ID_RISKOBJECT")) ) AS "Limit1"
WHERE (0 = "Limit1"."F_STATUS") OR (1 = "Limit1"."F_STATUS")

Answer 1

确定。唯一的解决方案，就是我在初始表中读到列表时发现的。不幸的是，不是我的意思，但它确实有效。

 AIds = (from x in 
        (
           context.RISK_T_ASSESS_HIST.Where(x => x.ID_RISKOBJECT.HasValue && x.F_CREATEDON >= Freq.StartDate && x.F_CREATEDON <= Freq.EndDate)
           .Select(x => new { x.ID_RISKOBJECT, x.F_CREATEDON, x.F_STATUS }).ToList()
        )      
        group x by x.ID_RISKOBJECT into gr
        let lastCreated = gr.Max(p => p.F_CREATEDON)
        select new
        {
           ObjId = gr.Key
           ,
           LastStatus = gr.Where(p => p.F_CREATEDON == lastCreated && p.ID_RISKOBJECT == gr.Key).Select(p => p.F_STATUS).FirstOrDefault()
        }).Where(x => x.LastStatus == 0 || x.LastStatus == 1).Select(x => x.ObjId.Value).ToArray();

此问题实体框架将在其论坛上作为错误传递。

外部应用于.net 4.5和实体框架

1 个答案: