Make group by in outter join LINQ to entity - entity-framework

Question

I use Entity Framework-6.
I have this code(outter join, LINQ to entity):
var inspectionSitesConjection = (from st in sites
join ir in inspectionReview on st.Id equals ir.SiteId into g
from subsite in g.DefaultIfEmpty()
select new GeneralReportViewModel
{
siteName = subsite.Site.Name,
address = subsite.Site.Description,
inspectionDate = subsite.DateReview,
siteType = subsite.Site.SiteType.Description,
frequency = subsite.InspectionFrequency.Name,
status = subsite.IsNormal,
}).AsNoTracking();
I need to make group by siteName and frequency.
Is it pussable to make group by inside LINQ above?

Answer 1

Here is a starting point:
var grouped = inspectionSitesConjection
.GroupBy(item => new { item.siteName, item.frequency });
But note that the result (as you may see in Queryable.GroupBy documentation) is no more IQueryable<GeneralReportViewModel> but IQueryable<IGrouping<Key, GeneralReportViewModel>> where Key is anonymous type having siteName and frequency properties.
I'm providing this just because you specifically asked. It's not quite clear what are you trying to achieve with that query. Also, once you decided to use explicit join, then use the joined table instead of navigation property, and take into account that subsite can be null due to outer join.
from st in sites
join ir in inspectionReview on st.Id equals ir.SiteId into g
from subsite in g.DefaultIfEmpty()
select new GeneralReportViewModel
{
siteName = st.Name,
address = st.Description,
siteType = st.SiteType.Description,
inspectionDate = subsite.DateReview, // problem if subsite == null
frequency = subsite.InspectionFrequency.Name, // problem if subsite == null
status = subsite.IsNormal, // problem if subsite == null
})