LINQ to SQL - Left Outer Join with multiple join conditions
- by dan
I have the following SQL which I am trying to translate to LINQ:
SELECT f.value
FROM period as p
LEFT OUTER JOIN facts AS f ON p.id = f.periodid AND f.otherid = 17
WHERE p.companyid = 100
I have seen the typical implementation of the left outer join (ie. into x from y in x.DefaultIfEmpty() etc.) but am unsure how to introduce the other join condition ('AND f.otherid = 17')
EDIT
Why is the 'AND f.otherid = 17' condition part of the JOIN instead of in the WHERE clause?
Because f may not exist for some rows and I still want these rows to be included. If the condition is applied in the WHERE clause, after the JOIN - then I don't get the behaviour I want.
Unfortunately this:
from p in context.Periods
join f in context.Facts on p.id equals f.periodid into fg
from fgi in fg.DefaultIfEmpty()
where p.companyid == 100 && fgi.otherid == 17
select f.value
seems to be equivalent to this:
SELECT f.value
FROM period as p
LEFT OUTER JOIN facts AS f ON p.id = f.periodid
WHERE p.companyid = 100 && AND f.otherid = 17
which is not quite what I'm after.
