首先激活LINQKit，只需要配置DbContextOptions即可：

builder
    .UseSqlServer(connectionString) // or any other provider
    .WithExpressionExpanding();     // enabling LINQKit extension

然后，您可以重复使用以下表达式：

public List<Ticket> GetTicketsForBuild(Build build)
{
    Expression<Func<Build, Build, int>> CompareBuilds = (first, second) =>
        // complex logic, simplified for the sake of example
        first.Version == second.Version ? 0 : (first.Version < second.Version ? -1 : 1);
    
    return _myDbContext.Ticket
        .Where(x => CompareBuilds.Invoke(x.BuildIntroducedIn, build) <= 0)
        .Where(x => x.IsPublic ?
            CompareBuilds.Invoke(x.BuildResolvedIn, build) < 0 :
            CompareBuilds.Invoke(x.BuildResolvedIn, build) > 0)
        .ToList();
}

但通常这样的函数在其他查询中很方便，我们可以用更通用的方式来做：

public static class QueryHelper
{
    [Expandable(nameof(CompareBuildsImpl))]
    public static int CompareBuilds(Build first, Build second)
    {
        throw new InvalidOperationexception();
    }

    private static Expression<Func<Build, Build, int>> CompareBuildsimpl()
    {
        return (first, second) =>
            // complex logic, simplified for the sake of example
            first.Version == second.Version ? 0 : (first.Version < second.Version ? -1 : 1);
    }
}

并在查询中重用：

public List<Ticket> GetTicketsForBuild(Build build)
{    
    return _myDbContext.Ticket
        .Where(x => QueryHelper.CompareBuilds(x.BuildIntroducedIn, build) <= 0)
        .Where(x => x.IsPublic ?
            QueryHelper.CompareBuilds(x.BuildResolvedIn, build) < 0 :
            QueryHelper.CompareBuilds(x.BuildResolvedIn, build) > 0)
        .ToList();
}

还有其他的库做同样的事情，我已经收集了其中的一些here