IQueryable 丢失了 ORDER BY

Question

谁能解释为什么会这样？

Dim lReturn As IQueryable(Of Inventory) = context.Inventories.OrderBy(Function(o) o.SortOrder)

'' --- In the sql profiler, I can see Order by is added
'' Dim lst = lReturn.ToList 

If Not loggedInUser.IsAdmin Then
    lReturn = lReturn.Where(Function(x) x.AdminOnly = False)
    '' --- In the sql profiler, I can see Order by is added
    '' Dim lst = lReturn.ToList 

    lReturn = From f In lReturn
              Group Join a In context.AssignServices On f.ID Equals a.Id Into fas = Group
              From a In fas.Where(Function(x) x.AgentId = loggedInUser.CompanyId).DefaultIfEmpty()
              Where a.Assign = True OrElse f.isVisibleToAllAgents = True
              Select f
    '' --- In the sql profiler, I can see **Order by is not included**
    Dim lst = lReturn.ToList     ''*Problem is here*

End If

lReturn 的开头已经包含了 Order By，这是一个 Lambda 表达式。如果用户不是管理员，最后的 Linq 查询由于某种原因不包括排序依据。我正在使用 sql 探查器来了解查询的外观，如下所示

exec sp_executesql N'SELECT 
[Extent1].[ID] AS [ID], 
[Extent1].[Name] AS [Name], 
.........
[Extent1].[SortOrder] AS [SortOrder]
FROM  [dbo].[Inventories] AS [Extent1]
LEFT OUTER JOIN [dbo].[AssignService] AS [Extent2] ON ([Extent1].[ID] = [Extent2].[Id]) AND ([Extent2].[AgentId] = @p__linq__0)
WHERE (0 = [Extent1].[AdminOnly]) AND ([Extent2].[Assign] = 1 OR [Extent1].[isVisibleToAllAgents] = 1) ,N'@p__linq__0 int',@p__linq__0=112

这是正常行为吗？还是我错过了什么？

Answer 1

基于 LINQ 的 ORM 已经放宽了关于支持哪些特定模式排序的规则。始终支持的（根据我的经验）是在查询末尾进行排序，后面只有 Where 和 Select 操作。

可能顺序在加入时丢失了。不让我吃惊。

IQueryable 丢失了 ORDER BY

IQueryable losing the ORDER BY

linq

vb.net

lambda

sql-server-profiler