Linq left join and group by issue

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Hi Everyone,
I am very new to linq,

this is the result i am looking for in linq, which i have done in the sql 
 category name  categoryID   count (number of products)
   Movies         2           65
   PS4 Games      3           26
   Printers       8           0
   Head phones    9           0
   Speakers       10          0

i have tried that, it worked, but it has turned "0" into "1". i mean, where no product exist in a category it should say "0" instead it says "1"
 
thanks in advance

What I have tried:

var results = from procat in this.objDB.tbl_category
              join product in this.objDB.tbl_Product on procat.cat_id equals product.pro_fk_cat_id into productdetail
              from productdetaildata in productdetail.DefaultIfEmpty()
              select new CategoryModel
              {
                  cat_name = procat.cat_name,
                  cat_id = procat.cat_id,
                  related_count = productdetaildata.pro_fk_cat_id
              };


IEnumerable<CategoryModel> CategoryList = results.GroupBy(x => x.cat_id, (key, _data) => new CategoryModel
{
    cat_name = _data.Select(x => x.cat_name).FirstOrDefault(),
    cat_id = _data.Select(x => x.cat_id).FirstOrDefault(),
    related_count = _data.Count()
});

Posted 16-Mar-21 0:41am

chan200uk

Updated 16-Mar-21 1:12am

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Richard Deeming · Answer 1 · 2021-03-16T01:12:00

Not at all clear, since you didn't describe your table structure nor show your working SQL query. But guessing based on the names, all you need is something like this:

C#

IEnumerable<CategoryModel> CategoryList = 
    from procat in this.objDB.tbl_category
    join product in this.objDB.tbl_Product on procat.cat_id equals product.pro_fk_cat_id into productdetail
    from productdetaildata in productdetail.DefaultIfEmpty()
    select new CategoryModel
    {
        cat_name = procat.cat_name,
        cat_id = procat.cat_id,
        related_count = productdetaildata.Count()
    };