我们在单个开发人员机器和一些客户端上遇到问题。单个 Linq 查询 生成两个不同的 SQL 查询。问题实际上是第二个查询有firebird不支持的“OUTER APPLY”语句。我们认为这不是代码问题，而是环境问题，但我会粘贴代码。
林克：
AIds = (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();
带有外部应用的 SQL
SELECT
"G"."ID_RISKOBJECT" AS "ID_RISKOBJECT"
FROM (SELECT
"C"."A1" AS "C1",
"C"."K1" AS "ID_RISKOBJECT"
FROM ( SELECT
"E"."ID_RISKOBJECT" AS "K1",
MAX("E"."F_CREATEDON") AS "A1"
FROM "RISK_T_ASSESS_HIST" AS "E"
WHERE (("E"."ID_RISKOBJECT" IS NOT NULL) AND ("E"."F_CREATEDON" >= @p__linq__0)) AND ("E"."F_CREATEDON" <= @p__linq__1)
GROUP BY "E"."ID_RISKOBJECT"
) AS "C" ) AS "G"
OUTER APPLY (SELECT FIRST (1)
"I"."F_STATUS" AS "F_STATUS"
FROM "RISK_T_ASSESS_HIST" AS "I"
WHERE (((("I"."ID_RISKOBJECT" IS NOT NULL) AND ("I"."F_CREATEDON" >= @p__linq__0)) AND ("I"."F_CREATEDON" <= @p__linq__1)) AND (("G"."ID_RISKOBJECT" = "I"."ID_RISKOBJECT") OR (("G"."ID_RISKOBJECT" IS NULL) AND ("I"."ID_RISKOBJECT" IS NULL)))) AND (("I"."F_CREATEDON" = "G"."C1") AND ("I"."ID_RISKOBJECT" = "G"."ID_RISKOBJECT")) ) AS "J"
WHERE (0 = "J"."F_STATUS") OR (1 = "J"."F_STATUS")
工作 SQL
SELECT
"B"."ID_RISKOBJECT" AS "ID_RISKOBJECT"
FROM ( SELECT
"C"."ID_RISKOBJECT" AS "ID_RISKOBJECT",
(SELECT FIRST (1)
"I"."F_STATUS" AS "F_STATUS"
FROM "RISK_T_ASSESS_HIST" AS "I"
WHERE (((("I"."ID_RISKOBJECT" IS NOT NULL) AND ("I"."F_CREATEDON" >= @p__linq__0)) AND ("I"."F_CREATEDON" <= @p__linq__1)) AND (("C"."ID_RISKOBJECT" = "I"."ID_RISKOBJECT") OR (("C"."ID_RISKOBJECT" IS NULL) AND ("I"."ID_RISKOBJECT" IS NULL)))) AND (("I"."F_CREATEDON" = "C"."C1") AND ("I"."ID_RISKOBJECT" = "C"."ID_RISKOBJECT"))) AS "C1"
FROM ( SELECT
"D"."A1" AS "C1",
"D"."K1" AS "ID_RISKOBJECT"
FROM ( SELECT
"F"."ID_RISKOBJECT" AS "K1",
MAX("F"."F_CREATEDON") AS "A1"
FROM "RISK_T_ASSESS_HIST" AS "F"
WHERE (("F"."ID_RISKOBJECT" IS NOT NULL) AND ("F"."F_CREATEDON" >= @p__linq__0)) AND ("F"."F_CREATEDON" <= @p__linq__1)
GROUP BY "F"."ID_RISKOBJECT"
) AS "D"
) AS "C"
) AS "B"
WHERE (0 = "B"."C1") OR (1 = "B"."C1")
为 MSSQL 引擎生成的查询（我们的 APP 中支持两个 db 引擎）
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 [dbo].[RISK_T_ASSESS_HIST] AS [Extent1]
WHERE ([Extent1].[ID_RISKOBJECT] IS NOT NULL) AND ([Extent1].[F_CREATEDON] >= @p__linq__0) AND ([Extent1].[F_CREATEDON] <= @p__linq__1)
GROUP BY [Extent1].[ID_RISKOBJECT]
) AS [GroupBy1] ) AS [Project1]
OUTER APPLY (SELECT TOP (1)
[Extent2].[F_STATUS] AS [F_STATUS]
FROM [dbo].[RISK_T_ASSESS_HIST] AS [Extent2]
WHERE ([Extent2].[ID_RISKOBJECT] IS NOT NULL) AND ([Extent2].[F_CREATEDON] >= @p__linq__0) AND ([Extent2].[F_CREATEDON] <= @p__linq__1) 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 [Limit1].[F_STATUS] IN (0,1)