I have this Ecto Query:
books = (from books in Mango.Books.Book,
left_join: records in assoc(books, :records),
where: books.institute_id == ^claims["institute_id"],
where: not is_nil(records.returned_at), # how to insert "not" or omit it based on the value of params["returned"]
group_by: [records.book_id, books.id, records.due_for_return, records.returned_at],
select: %{
"record_id" => max(records.id),
"title" => books.title,
"book_id" => books.id,
"due_for_return" => records.due_for_return,
"returned_at" => records.returned_at}
)
|> MangoWeb.Filters.Books.build_query(conn, params)
|> Repo.paginate(page: params["page"], page_size: params["per_page"])
I will be passing to to the controller action a parameter named returned
with the value of 0
or 1
. On the second where
expression I want to either specify not
or omit it based on the value of params["retruned"]
.
Any idea how could this be done? Thank you.