安装后.Net 4.5
,EF 生成的查询存在问题。 linq 中的相同查询到 .Net 4.0
工作正常。我正在使用 Firebird 数据库,它不支持命令 OUTER APPLY
.有什么方法可以修改以下查询 linq,使其在 .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。网络 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")
最佳答案
好的。唯一的解决方案,这是我在阅读列表的初始表时发现的。不幸的是,并不完全是我的意思,但它有效。
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 Entity Framework 并将在其论坛上作为错误传递。
关于.net - .net 4.5 和 Entity Framework 中的外部应用,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/17083304/