Query: optimize query sql patterns like `(x || y) && !y` into `x && !y` when y is non-nullable

Open
#26,064 4 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp, sql
Domain
backend, databases

Research direction

Start by reproducing the C# example with the SQL Server provider and inspect the LINQ translation used by ToQueryString(). Add a regression test for the non-nullable boolean pattern, and consider the work done when the generated SQL removes the redundant OR/IS NULL branch and matches the expected behavior.

Written by the indexing model from the issue text.

Description

area-query customer-reported
Include your code
public class Test
{
    public Guid Id { get; set; }

    public Guid? UserId { get; set; }
}

public partial class DemoContext : DbContext
{
    public DemoContext()
    {
    }

    public DemoContext(DbContextOptions<DemoContext> options)
        : base(options)
    {
    }

    public virtual DbSet<Test> Tests { get; set; }
}

var services = new ServiceCollection();
services.AddDbContext<DemoContext>();
var serviceProvider = services.BuildServiceProvider();

var demoContext = serviceProvider.GetRequiredService<DemoContext>();
var userId = Guid.NewGuid();
var sql = demoContext.Tests.Where(a => a.UserId != userId && a.UserId.HasValue).ToQueryString();
Console.WriteLine(sql);
Expected Behavior
DECLARE @__userId_0 uniqueIdentifier = 'd7deb76b-b725-4285-a736-2477dedb927b';

SELECT [t].[Id], [t].[UserId]
FROM [Tests] AS [t]
WHERE [t].[UserId] IS NOT NULL AND ([t].[UserId] <> @__userId_0)
Actual Behavior
DECLARE @__userId_0 uniqueIdentifier = '8286edc4-2a82-49d7-b50c-1832964b94e5';

SELECT [t].[Id], [t].[UserId]
FROM [Tests] AS [t]
WHERE (([t].[UserId] <> @__userId_0) OR [t].[UserId] IS NULL) AND [t].[UserId] IS NOT NULL
Include provider and version information

EF Core version:6.0.0-rc.1.21452.10
Database provider: Microsoft.EntityFrameworkCore.SqlServer
Target framework: .NET 6.0
Operating system:Win10
IDE: Visual Studio 2022 17.0

Dominant language
C#
Stars
14.8k
Forks
3.4k
Avg merge
2d 5h
Merged PRs (30d)
134

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from dotnet/efcore

All issues in dotnet/efcore

Similar issues

More C# issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.