Question

I’m trying to get data from two tables. Todo_Lists and Todo_Items. I manged to join the two like this:

from list in dataContext.Todo_Lists
from item in dataContext.Todo_List_Items
where list.UserID == userID && list.ListID == item.ListID
select new
{
    ListID = list.ListID,
    ListName = list.ListName, 
    ItemID = item.ItemID, 
    ItemName = item.ItemName 
};

That’s all good in the hood if I just want the lists with Items on them. But I need to return all the lists and where there are Items I need them to be joined in.

Thankfull for any information.

Answer 1

sounds like a left outer join: (untested)

from list in dataContext.Todo_Lists
where list.UserID == userID
join itemTemp in dataContext.Todo_List_Items on list.ListID equals item.ListID into itemGroup
from item in itemGroup.DefaultIfEmpty()

select new
{
    ListID = list.ListID,
    ListName = list.ListName, 
    ItemID = item == null? null : item.ItemID, 
    ItemName = item == null? null : item.ItemName 
};

you’ll probably need to cast the nulls for the conditional to work – I left it out cos I don’t know the type. See here for more info on left outer joins using linq.