I would think that f
would be an Option
, so this something like this should work:
join(MySchema.users,
MySchema.folders.leftOuter,
MySchema.accounts.leftOuter)((u, f, a) =>
select(u, f, a)
on (u.idField === f.map(_.userId),
f.map(_.idField) === a.map(_.folderId))
)