LINQ加入/分组问题

Question

So I am stuck again...

I have three tables that I am trying to join and group with linq; Company, Notices and Requests.

• A company could have many notices.

• A notice have a SubcategoryId and a CompanyId

• A request have a SubcategoryId.

My aim here is to get a list of companies and for each company get a list of their noticed subcategories and for each noticed subcategory the requests within that subcategory

Ex: Company x is monitoring the subcategories 4 and 7. Show him what requests we've got within those subcats.

This is how I do it for only one company. But I can't solve the grouping and joins when I need a list of multiple companies.

Company company = db.Companies.Where(x=>x.UserId == 10).FirstOrDefault();
            var requestByNotices =
            from notice in company.Notices
            join request in db.Requests.Where(z => z.IsApproved &
                 z.Status.Status == "Active") on notice.SubcategoryId equals
                 request.Subcategoryid

UPDATE

Let me rephrase my questions.

This query is producing a table with the results I am looking for:

SELECT Companies.CompanyId, Companies.Name, Account.Email, Notices.SubcategoryId, Requests.FriendlyName FROM Companies
INNER JOIN Notices  ON Companies.CompanyId = Notices.CompanyId 
INNER JOIN Account  ON Account.UserId = Companies.Uid
INNER JOIN Requests ON Notices.SubcategoryId = Requests.Subcategoryid 
WHERE Requests.StartDate > '2013-12-22';  

But instead of generating a flat list I would like to translate this into to linq but also group by CompanyId. So each company is represented by one row only and within that company I can get the requests.

So instead of a list like this:

CompanyId   Name   Email            SubcategoryId     FriendlyName
1           Test   test@test.com    2                 x
1           Test   test@test.com    4                 y

I would like to have it like this:

CompanyId   Name   Email            GroupOfRequests  
1           Test   test@test.com    contains two 

Thankful for any help!

Answer 1

UPDATED: if i understand right you want something like this

var result =
        from company in db.Companies
        from notice in company.Notices
        join request in db.Requests.Where(z => z.IsApproved &&
             z.Status.Status == "Active") on notice.SubcategoryId equals request.Subcategoryid
        group new {notice, request } by company into gr           
        select new {gr.Key, Value = gr.ToList() }

UPDATE2
for your sql it seems like this

from company in db.Companies
join notice in db.Notices on company.CompanyId equals notice.CompanyId
join account in db.Account on company.Uid equals account.UserId
join request in db.Requests on notice.SubcategoryId equals request.SubcategoryId

group new {notice, request} by new {company, account} into g
select new {g.Key, value = g}