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按照entityframework.codeplex.com的建议，我将此问题与标记entity-framework一起发布。LINQ生成不正确的SQL
数据库：在PostgreSQL 9.1 驱动程序：2.0.12 Npgsql的
LINQ查询：
var q1 = customerComplaints
.Where(x => x.ParentId == null)
.Except(customerComplaints
.Where(x => customerComplaints
.Any(c => (c.ParentId == x.Id))));
var q2 =
(from a in customerComplaints
join b in
(customerComplaints.Where(a => a.ParentId != null)
.GroupBy(a => a.ParentId)
.Select(b => new { ParentId = b.Key, CreatedDate = b.Max(t => t.CreatedDate) }))
on a.ParentId equals b.ParentId
where a.CreatedDate == b.CreatedDate
select a);
q1 = q1.Union(q2);
// Apply Sorting
if (string.IsNullOrEmpty(sorting) || sorting.Equals("CustomerName ASC")) {
q1 = q1.OrderBy(p => p.Customer.Name);
} else if (sorting.Equals("CustomerName DESC")) {
q1 = q1.OrderByDescending(p => p.Customer.Name);
} else if (sorting.Equals("ManagerName ASC")) {
q1 = q1.OrderBy(p => p.Manager.LastName);
} else if (sorting.Equals("ManagerName DESC")) {
q1 = q1.OrderByDescending(p => p.Manager.LastName);
} else if (sorting.Equals("AssignedName ASC")) {
q1 = q1.OrderBy(p => p.Assigned.LastName);
} else if (sorting.Equals("AssignedName DESC")) {
q1 = q1.OrderByDescending(p => p.Assigned.LastName);
} else if (sorting.Equals("StatusName ASC")) {
q1 = q1.OrderBy(p => p.StatusId);
} else if (sorting.Equals("StatusName DESC")) {
q1 = q1.OrderByDescending(p => p.StatusId);
} else if (sorting.Equals("ComplaintType ASC")) {
q1 = q1.OrderBy(p => p.ComplaintTypeId);
} else if (sorting.Equals("ComplaintType DESC")) {
q1 = q1.OrderByDescending(p => p.ComplaintTypeId);
} else if (sorting.Equals("CreatedDate ASC")) {
q1 = q1.OrderBy(p => p.CreatedDate);
} else if (sorting.Equals("CreatedDate DESC")) {
q1 = q1.OrderByDescending(p => p.CreatedDate);
}
// Perform paging and execute query
var result = q1.Skip(startIndex).Take(pageSize).ToList();
生成的SQL
SELECT
"Limit1"."C1" AS "C1"
"Limit1"."C2" AS "C2"
"Limit1"."C3" AS "C3"
"Limit1"."C4" AS "C4"
"Limit1"."C5" AS "C5"
"Limit1"."C6" AS "C6"
"Limit1"."C7" AS "C7"
"Limit1"."C8" AS "C8"
"Limit1"."C9" AS "C9"
"Limit1"."C10" AS "C10"
"Limit1"."C11" AS "C11"
"Limit1"."C12" AS "C12"
"Limit1"."C13" AS "C13"
"Limit1"."C14" AS "C14"
"Limit1"."C15" AS "C15"
"Limit1"."C16" AS "C16"
"Limit1"."C17" AS "C17"
"Limit1"."C18" AS "C18"
"Limit1"."C19" AS "C19"
"Limit1"."C20" AS "C20"
"Limit1"."C21" AS "C21"
"Limit1"."C22" AS "C22"
FROM
(SELECT DISTINCT
"UnionAll1"."C1" AS "C1"
"UnionAll1"."C2" AS "C2"
"UnionAll1"."C3" AS "C3"
"UnionAll1"."C4" AS "C4"
"UnionAll1"."C5" AS "C5"
"UnionAll1"."C6" AS "C6"
"UnionAll1"."C7" AS "C7"
"UnionAll1"."C8" AS "C8"
"UnionAll1"."C9" AS "C9"
"UnionAll1"."C10" AS "C10"
"UnionAll1"."C11" AS "C11"
"UnionAll1"."C12" AS "C12"
"UnionAll1"."C13" AS "C13"
"UnionAll1"."C14" AS "C14"
"UnionAll1"."C15" AS "C15"
"UnionAll1"."C16" AS "C16"
"UnionAll1"."C17" AS "C17"
"UnionAll1"."C18" AS "C18"
"UnionAll1"."C19" AS "C19"
"UnionAll1"."C20" AS "C20"
"UnionAll1"."C21" AS "C21"
"UnionAll1"."C22" AS "C22"
FROM
(SELECT
"Except1"."Id" AS "C1"
"Except1"."ManagerId" AS "C2"
"Except1"."AssignedId" AS "C3"
"Except1"."ComplaintTypeId" AS "C4"
"Except1"."RootCauseId" AS "C5"
"Except1"."StatusId" AS "C6"
"Except1"."ResultingFromId" AS "C7"
"Except1"."RespParty" AS "C8"
"Except1"."Condition" AS "C9"
"Except1"."Containment" AS "C10"
"Except1"."CorrectiveAction" AS "C11"
"Except1"."ProductRejected" AS "C12"
"Except1"."IssueDate" AS "C13"
"Except1"."DueDate" AS "C14"
"Except1"."Approved" AS "C15"
"Except1"."ApprovedById" AS "C16"
"Except1"."ApprovedDate" AS "C17"
"Except1"."RejectionDetail" AS "C18"
"Except1"."Parent" AS "C19"
"Except1"."ParentId" AS "C20"
"Except1"."CreatedDate" AS "C21"
"Except1"."CreatedId" AS "C22"
FROM
(SELECT
"Extent1"."Id" AS "Id",
"Extent1"."ManagerId" AS "ManagerId",
"Extent1"."AssignedId" AS "AssignedId",
"Extent1"."ComplaintTypeId" AS "ComplaintTypeId",
"Extent1"."RootCauseId" AS "RootCauseId",
"Extent1"."StatusId" AS "StatusId",
"Extent1"."ResultingFromId" AS "ResultingFromId",
"Extent1"."RespParty" AS "RespParty",
"Extent1"."Condition" AS "Condition",
"Extent1"."Containment" AS "Containment",
"Extent1"."CorrectiveAction" AS "CorrectiveAction",
"Extent1"."ProductRejected" AS "ProductRejected",
"Extent1"."IssueDate" AS "IssueDate",
"Extent1"."DueDate" AS "DueDate",
"Extent1"."Approved" AS "Approved",
"Extent1"."ApprovedById" AS "ApprovedById",
"Extent1"."ApprovedDate" AS "ApprovedDate",
"Extent1"."RejectionDetail" AS "RejectionDetail",
"Extent1"."Parent" AS "Parent",
"Extent1"."ParentId" AS "ParentId",
"Extent1"."CreatedDate" AS "CreatedDate",
"Extent1"."CreatedId" AS "CreatedId"
FROM
"dbo"."CorrectiveActionRequest" AS "Extent1"
WHERE
"Extent1"."ParentId" IS NULL
EXCEPT
SELECT
"Extent2"."Id" AS "Id",
"Extent2"."ManagerId" AS "ManagerId",
"Extent2"."AssignedId" AS "AssignedId",
"Extent2"."ComplaintTypeId" AS "ComplaintTypeId",
"Extent2"."RootCauseId" AS "RootCauseId",
"Extent2"."StatusId" AS "StatusId",
"Extent2"."ResultingFromId" AS "ResultingFromId",
"Extent2"."RespParty" AS "RespParty",
"Extent2"."Condition" AS "Condition",
"Extent2"."Containment" AS "Containment",
"Extent2"."CorrectiveAction" AS "CorrectiveAction",
"Extent2"."ProductRejected" AS "ProductRejected",
"Extent2"."IssueDate" AS "IssueDate",
"Extent2"."DueDate" AS "DueDate",
"Extent2"."Approved" AS "Approved",
"Extent2"."ApprovedById" AS "ApprovedById",
"Extent2"."ApprovedDate" AS "ApprovedDate",
"Extent2"."RejectionDetail" AS "RejectionDetail",
"Extent2"."Parent" AS "Parent",
"Extent2"."ParentId" AS "ParentId",
"Extent2"."CreatedDate" AS "CreatedDate",
"Extent2"."CreatedId" AS "CreatedId"
FROM
"dbo"."CorrectiveActionRequest" AS "Extent2"
WHERE EXISTS
(SELECT
1 AS "C1"
FROM
"dbo"."CorrectiveActionRequest" AS "Extent3"
WHERE
"Extent3"."ParentId"="Extent2"."Id")) AS "Except1"
UNION ALL
SELECT
"Extent4"."Id" AS "Id",
"Extent4"."ManagerId" AS "ManagerId",
"Extent4"."AssignedId" AS "AssignedId",
"Extent4"."ComplaintTypeId" AS "ComplaintTypeId",
"Extent4"."RootCauseId" AS "RootCauseId",
"Extent4"."StatusId" AS "StatusId",
"Extent4"."ResultingFromId" AS "ResultingFromId",
"Extent4"."RespParty" AS "RespParty",
"Extent4"."Condition" AS "Condition",
"Extent4"."Containment" AS "Containment",
"Extent4"."CorrectiveAction" AS "CorrectiveAction",
"Extent4"."ProductRejected" AS "ProductRejected",
"Extent4"."IssueDate" AS "IssueDate",
"Extent4"."DueDate" AS "DueDate",
"Extent4"."Approved" AS "Approved",
"Extent4"."ApprovedById" AS "ApprovedById",
"Extent4"."ApprovedDate" AS "ApprovedDate",
"Extent4"."RejectionDetail" AS "RejectionDetail",
"Extent4"."Parent" AS "Parent",
"Extent4"."ParentId" AS "ParentId",
"Extent4"."CreatedDate" AS "CreatedDate",
"Extent4"."CreatedId" AS "CreatedId"
FROM
"dbo"."CorrectiveActionRequest" AS "Extent4"
INNER JOIN
(SELECT
"Extent5"."ParentId" AS "K1",
CAST
(max("Extent5"."CreatedDate") AS timestamp) AS "A1"
FROM
"dbo"."CorrectiveActionRequest" AS "Extent5"
WHERE
"Extent5"."ParentId" IS NOT NULL
GROUP BY
"Extent5"."ParentId") AS "GroupBy1"
ON
(("Extent4"."ParentId"="GroupBy1"."K1")
OR
(("Extent4"."ParentId" IS NULL)
AND
("GroupBy1"."K1" IS NULL)))
AND
("Extent4"."CreatedDate"="GroupBy1"."A1")) AS "UnionAll1") AS "Limit1"
ORDER BY "Distinct1"."C7" ASC
OFFSET 0
LIMIT 10
罪魁祸首是在最后：
("Extent4"."CreatedDate"="GroupBy1"."A1")) AS "UnionAll1") AS "Limit1"
ORDER BY "Distinct1"."C7" ASC
OFFSET 0
LIMIT 10
它尝试按Distinct1排序，但在生成的SQL查询中没有其他位置存在此标识符。我一直试图调试这几天，并注意到它依赖于我选择排序。例如，按Customer.Name排序将产生一个工作查询。按照CreatedDate排序不会。
你使用哪个数据库？ – Slauma
是的，这是无效的SQL没错，报告一个错误。 –
@Slauma我使用PostreSQL和Npgsql作为驱动程序。 – Alex