Entity framework generated SQL is different from 2.2 to 7

Alexander Angelo 6

I recently upgraded a .NET core 2.1 web app to .NET 7 with upgrading EntityFrameworkCore to 7.0.1. 

a statement that use "Include" is now producing Sql queries with LEFT JOIN whereas with 2.1, they produce a mix of LEFT and INNER joins.

 _dbContext.T1
   .Include(t11 => t11.T11)
      .ThenInclude(t12 => t12.T12)
   .Include(p => p.P)
   .AsNoTracking()

produces

2.1 :

FROM T12
  INNER JOIN (
    SELECT DISTINCT ..................
    FROM T11
      INNER JOIN (
        SELECT ......
        FROM T1 
        LEFT JOIN P .........................

7 : 

FROM T1
LEFT JOIN P
 LEFT JOIN (
    SELECT ------
    FROM T11 
      LEFT JOIN T12
      -----

Wonder why the latest EFCore 7 produces a different SQL query to 2.1


I was expecting the generated SQL to be the same in both version of EFCore

Wenbin Geng 716 Microsoft Vendor

Hi, I used EF Core7.0.1 and tested the query statement you provided. The entity class used is:

    public class T1
    {
        public int id {  get; set; }

        public t11 T11 { get; set; }

        public p P { get; set; }
    }

    public class t11
    {
        public int id { get; set; }

        public t12 T12 { get; set; }
    }

    public class t12
    {
        public int id { get; set; }
    }

    public class p
    {
        public int id { get; set; }
    }

The generated sql is:

SELECT [t].[id], [t].[Pid], [t].[T11id], [t0].[id], [t0].[T12id], [t1].[id], [p].[id]
FROM [T1] AS [t]
INNER JOIN [t11] AS [t0] ON [t].[T11id] = [t0].[id]
INNER JOIN [t12] AS [t1] ON [t0].[T12id] = [t1].[id]
INNER JOIN [p] AS [p] ON [t].[Pid] = [p].[id]

This seems to be a discrepancy with the information you provided, so you will need to provide more information. For example, your entity class information. This will help reproduce your issue.

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Entity framework generated SQL is different from 2.2 to 7