C# 如何正确地结合两个带条件的孙子表

我有一个使用EF4.4映射的现有Oracle数据库。当我试图从两个大的子表中查询数据时。我得到一个错误如下所述。我认为问题出在lambda查询中，但不确定它出了什么问题

表格

X
-XID
-VAL

A
-AID

BA
-BID
-AID

CA
-CID
-AID

BX
-BXID
-BID
-XID

CX
-CXID
-CID
-XID

查询：

var q = context.As.AsQueryable();
    q = q.Where(o=>o.BAs.Any(p=>p.BX.Any(t=>t.BXID==1)))
         .Union(
        q.Where(o=>o.CAs.Any(p=>p.CX.Any(t=>t.CXID==1))).AsQueryable<A>();

SELECT 
"Distinct1"."C1" AS "C1"
FROM ( SELECT DISTINCT 
    "UnionAll1"."AID" AS "C1",
    FROM  (SELECT 
        "Extent1"."AID" AS "AID"
        FROM "SCHEMA"."A" "Extent1"
        WHERE ( EXISTS (SELECT 
            1 AS "C1"
            FROM ( SELECT 
                "Extent2"."BID" AS "BID"
                FROM "SCHEMA"."BA" "Extent2"
                WHERE ("Extent1"."AID" = "Extent2"."AID")
            )  "Project1"
            WHERE ( EXISTS (SELECT 
                1 AS "C1"
                FROM "SCHEMA"."BX" "Extent3"
                WHERE (("Project1"."BID" = "Extent3"."BID") AND (1 = ( CAST(
"Extent3"."BXID" AS number(9,0)))))
            ))
        ))
    UNION ALL
        SELECT 
        "Extent4"."AID" AS "AID"
        FROM "SCHEMA"."A" "Extent4"
        WHERE ( EXISTS (SELECT 
            1 AS "C1"
            FROM ( SELECT 
                "Extent5"."CID" AS "CID"
                FROM "SCHEMA"."CA" "Extent5"
                WHERE ("Extent4"."AID" = "Extent5"."AID")
            )  "Project5"
            WHERE ( EXISTS (SELECT 
                1 AS "C1"
                FROM "SCHEMA"."CX" "Extent6"
                WHERE (("Project5"."CID" = "Extent6"."CID") AND (1 = ( CAST(
"Extent6"."CXID" AS number(9,0)))))
            ))
        ))) "UnionAll1"
)  "Distinct1"

ORA-00904: "Extent1"."AID": invalid identifier     

错误：

var q = context.As.AsQueryable();
    q = q.Where(o=>o.BAs.Any(p=>p.BX.Any(t=>t.BXID==1)))
         .Union(
        q.Where(o=>o.CAs.Any(p=>p.CX.Any(t=>t.CXID==1))).AsQueryable<A>();

SELECT 
"Distinct1"."C1" AS "C1"
FROM ( SELECT DISTINCT 
    "UnionAll1"."AID" AS "C1",
    FROM  (SELECT 
        "Extent1"."AID" AS "AID"
        FROM "SCHEMA"."A" "Extent1"
        WHERE ( EXISTS (SELECT 
            1 AS "C1"
            FROM ( SELECT 
                "Extent2"."BID" AS "BID"
                FROM "SCHEMA"."BA" "Extent2"
                WHERE ("Extent1"."AID" = "Extent2"."AID")
            )  "Project1"
            WHERE ( EXISTS (SELECT 
                1 AS "C1"
                FROM "SCHEMA"."BX" "Extent3"
                WHERE (("Project1"."BID" = "Extent3"."BID") AND (1 = ( CAST(
"Extent3"."BXID" AS number(9,0)))))
            ))
        ))
    UNION ALL
        SELECT 
        "Extent4"."AID" AS "AID"
        FROM "SCHEMA"."A" "Extent4"
        WHERE ( EXISTS (SELECT 
            1 AS "C1"
            FROM ( SELECT 
                "Extent5"."CID" AS "CID"
                FROM "SCHEMA"."CA" "Extent5"
                WHERE ("Extent4"."AID" = "Extent5"."AID")
            )  "Project5"
            WHERE ( EXISTS (SELECT 
                1 AS "C1"
                FROM "SCHEMA"."CX" "Extent6"
                WHERE (("Project5"."CID" = "Extent6"."CID") AND (1 = ( CAST(
"Extent6"."CXID" AS number(9,0)))))
            ))
        ))) "UnionAll1"
)  "Distinct1"

ORA-00904: "Extent1"."AID": invalid identifier