Question

我有这个简单的查询，我希望有一个类别列表，并为每个类别提供内部产品的数量。

from category in categories
join product in products
    on category.Id equals product.Category_Id into productsPerCategories
select new Categories
{
    Category = category,
    products = productsPerCategories.Count()
};

但如果没有产品，我不希望该类别出现。使用我当前的构造，将会有内部没有产品的类别。我怎样才能做到这一点？

Answer 1

只需添加条件

where productsPerCategories.Any()

或

where productsPerCategories.Count() > 0

所以你的查询是：

from category in categories
join product in products on category.Id equals product.Category_Id into productsPerCategories
where productsPerCategories.Any()

            select new Categories
            {
                Category = category,
                products = productsPerCategories.Count()
            };

小组加入linq但仅限于孩子在场的地方

1 个答案: