(found this modifying the repro of [#2560](https://entityframework.codeplex.com/workitem/2560))
The code below produces more complex queries than before and introduces OUTER APPLY when it wasn’t necessary from EF 5.0 to EF 6.1.1. It seems that some of the query improvements we made removed the ability to simplify it.
```
using System;
using System.Data.Entity;
using System.Diagnostics;
using System.Linq;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
using (var context = new BugContext())
{
context.Database.Delete();
var minimumReproLinq =
from c in context.As.OrderBy(c => c.Id).Take(100)
let rel1 = c.B1
select new
{
c.Id,
Rel1 = new
{
c.B1.Id,
c.B1.Code,
}
};
var complexReproLinq =
from c in context.As.OrderBy(c => c.Id).Take(100)
let rel1 = c.B1
let rel2 = c.B2
select new
{
c.Id,
Rel1 = new
{
rel1.Id,
rel1.Code,
},
Rel2 = new
{
c.B2.Id,
c.B2.Code,
}
};
var minimumReproSql = minimumReproLinq.ToString();
var complexReproSql = complexReproLinq.ToString();
Console.WriteLine(minimumReproSql);
Console.WriteLine(complexReproSql);
}
}
}
public class BugContext : DbContext
{
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<A>()
.HasRequired(c => c.B1)
.WithRequiredPrincipal();
modelBuilder.Entity<A>()
.HasRequired(c => c.B2)
.WithRequiredPrincipal();
}
public DbSet<A> As { get; set; }
public DbSet<B> Bs { get; set; }
}
public class A
{
public int Id { get; set; }
public virtual B B1 { get; set; }
public virtual B B2 { get; set; }
}
public class B
{
public int Id { get; set; }
public string Code { get; set; }
}
}
```
For EF 6.1.2 we produce the following output:
__minimumReproSql:__
```
SELECT TOP (100)
[Extent1].[Id] AS [Id],
[Extent2].[Id] AS [Id1],
[Filter2].[Code] AS [Code]
FROM [dbo].[A] AS [Extent1]
LEFT OUTER JOIN [dbo].[B] AS [Extent2] ON [Extent1].[Id] = [Extent2].[Id]
OUTER APPLY (SELECT [Extent3].[Code] AS [Code]
FROM [dbo].[B] AS [Extent3]
LEFT OUTER JOIN (SELECT
[Extent4].[Id] AS [Id]
FROM [dbo].[B] AS [Extent4]
WHERE [Extent1].[Id] = [Extent4].[Id] ) AS [Project1] ON 1 = 1
WHERE [Extent1].[Id] = [Extent3].[Id] ) AS [Filter2]
ORDER BY [Extent1].[Id] ASC
```
__complexReproSql:__
```
SELECT TOP (100)
[Extent1].[Id] AS [Id],
[Extent2].[Id] AS [Id1],
[Extent2].[Code] AS [Code],
[Filter6].[Code1] AS [Code1]
FROM [dbo].[A] AS [Extent1]
LEFT OUTER JOIN [dbo].[B] AS [Extent2] ON [Extent1].[Id] = [Extent2].[Id]
OUTER APPLY (SELECT [Extent3].[Id] AS [Id1]
FROM [dbo].[B] AS [Extent3]
LEFT OUTER JOIN (SELECT
[Extent4].[Id] AS [Id]
FROM [dbo].[B] AS [Extent4]
WHERE [Extent1].[Id] = [Extent4].[Id] ) AS [Project1] ON 1 = 1
WHERE [Extent1].[Id] = [Extent3].[Id] ) AS [Filter2]
OUTER APPLY (SELECT [Extent5].[Code] AS [Code1]
FROM [dbo].[B] AS [Extent5]
LEFT OUTER JOIN (SELECT
[Extent6].[Id] AS [Id]
FROM [dbo].[B] AS [Extent6]
WHERE [Extent1].[Id] = [Extent6].[Id] ) AS [Project2] ON 1 = 1
LEFT OUTER JOIN (SELECT [Extent7].[Id] AS [Id2]
FROM [dbo].[B] AS [Extent7]
LEFT OUTER JOIN (SELECT
[Extent8].[Id] AS [Id]
FROM [dbo].[B] AS [Extent8]
WHERE [Extent1].[Id] = [Extent8].[Id] ) AS [Project3] ON 1 = 1
WHERE [Extent1].[Id] = [Extent7].[Id] ) AS [Filter5] ON 1 = 1
WHERE [Extent1].[Id] = [Extent5].[Id] ) AS [Filter6]
ORDER BY [Extent1].[Id] ASC
```
In EF 6.1.1 and previous versions down to 5.0 the result was this:
__minimumReproSql:__
```
SELECT TOP (100)
[Extent1].[Id] AS [Id],
[Extent2].[Id] AS [Id1],
[Extent2].[Code] AS [Code]
FROM [dbo].[A] AS [Extent1]
LEFT OUTER JOIN [dbo].[B] AS [Extent2] ON [Extent1].[Id] = [Extent2].[Id]
ORDER BY [Extent1].[Id] ASC
```
__complexReproSql:__
```
SELECT TOP (100)
[Extent1].[Id] AS [Id],
[Extent2].[Id] AS [Id1],
[Extent2].[Code] AS [Code]
FROM [dbo].[A] AS [Extent1]
LEFT OUTER JOIN [dbo].[B] AS [Extent2] ON [Extent1].[Id] = [Extent2].[Id]
ORDER BY [Extent1].[Id] ASC
```
Note that it is possible that there are simpler repros (e.g. with just one navigation property) but I wanted to show how the problem composes when there is more complexity.
Comments: Looks like this could be the same or similar tohttps://entityframework.codeplex.com/workitem/2413.
