Help with linq join - linq

Question

I have the following expression in linq (its a join) and i am selecting into "J" because i need to use J later (currently i just selecting J but once i have this fixed i plan on use J within another subquery after)
But it won't let me supply a where using the "V" side hence v.IdOFfice is invalid.
I have tried swapping around the joins and that what happens i can't use the "GVT"..
WIth specifying the where it works perfect but i need to specify 2 wheres that are present in the 2 tables ... hence IdOffice and IdTariff are in there own tables .. they are not both ....
(from gvt in Tariffs
join v in Items
on gvt.IdGroupItem equals v.IdGroupItem
into j
where v.IdOffice == 1 && gvt.IdTariff == 111
select j).Take(50)
Probably something silly, it appears the table specified after the join i am not able to use in the where?
Any ideas?
Thanks
This is basically what i am trying to achieve
from gvt in Tariffs
join v in Items
on gvt.IdGroupItem equals v.IdGroupItem
into j
where v.IdOffice == 1 && gvt.IdTariff == 111
select new
{
id = v.IdItem
Tariff = from j
{
test = j.TariffDesc,
test1 = j.TariffPrice
}
basicaly i end up with 1 record with Id and a field which as many tariffs inside - if this makes sense?
}
Query working great,
it would be nice to be able to use an extension method (c#) like so ... is this possible so i can dynamically set tariff ... so for example i do the query and i have an extension method (which i already use on simple queries) like so
public static IQueryable<Models.ItemTariffCol> WithTariffId(this IQueryable<Models.ItemTariffCol> qry, int tariffId)
{
return from t in qry
where t.IdTarifa == tariffId
select t;
}
this makes it very extensible ? If its a normal where i can do this but the query isn't in the where
Thank you.

Answer 1

You're doing a group join here, since you're using into. This means that for every gvt, you have not one Item, but possibly several (or none). The list of all items is stored in j, as an IEnumerable<Item>. If you want to select all tariffs for which there's at least one item with IdOffice == 1, then you can do it like this:
from gvt in Tariffs
join v in Items
on gvt.IdGroupItem equals v.IdGroupItem
into j
where gvt.IdTariff == 111 && j.Any(v => v.IdOffice == 1)
...
After the answer edit, it seems that you've started from the wrong direction as well - so far as I can see, you want a list of tariffs for every item, not the list of items for every tariff. For that, you need to reverse your join:
from item in Items
join tariff in Tariffs
on item.IdGroupItem equals tariff.IdGroupItem
into tariffs
where item.IdOffice == 1
select new
{
Id = item.IdItem,
Tariffs = from tariff in tariffs
where tariff.IdTariff == 111
select new { tariff.TariffDesc, tariff.TariffPrice }
}
Or you could filter tariffs right in the join:
from item in Items
join tariff in (from t in Tariffs where t.IdTariff == 111 select t)
on item.IdGroupItem equals tariff.IdGroupItem
into tariffs
where item.IdOffice == 1
select new
{
Id = item.IdItem,
Tariffs = from tariff in tariffs
select new { tariff.TariffDesc, tariff.TariffPrice }
}