performance - EF 核心 : How to translate "With table AS"

Question

我正在尝试使用 EF Core 来获取嵌套类别。问题是它太慢了。

看我的代码:

    public async Task<List<Category>> GetNestedCategoryAsync(Category category)
    {
        if (category is null)
            return new List<Category>();

        IQueryable<Category> query = db.Categories.Include(x => x.Childs).Include(x => x.Products).Where(x => category.Childs.Contains(x)).AsNoTracking();

        List<Category> nestedCategories = await query.ToListAsync();

        foreach (Category nestedCategory in nestedCategories.ToArray())
            nestedCategories.AddRange(await GetNestedCategoryAsync(nestedCategory));

        return nestedCategories;
    }

其实我不知道如何将这个 SQL 翻译成 EF .. 甚至可能吗？它的速度快了一千倍

With Categories_CTE As
(
Select *
From Categories
Where Id = 8692

Union All
Select t.*
From Categories t
Inner Join Categories_CTE c On c.Id = t.ParentId
)

Select c.*
From Categories_CTE c;

感谢您的任何提示

Answer 1

Entity Framework 永远不会生成 CTE，这对它来说太过分了。但是，您可以像这样通过 EF Core 使用您的 SQL:

var categories = db.Categories.FromSql("WITH Categories_CTE AS .......");