ruby on rails - Search by empty list for many-to-many relation using ransack -

i searched how pass empty array ransack, example:

@search = promotionsretailer.search(retailer_id_in: []) 

this sql statement:

"select `promotions_retailers`.* `promotions_retailers` " 

i found link, add -1 empty array, used search(retailer_id_in: ([] + [-1])).

1. any solution better solution?
2. how search using retailer_id in promotion table, if have many-to-many relation between promotions/retailers without using breaking table promotionsretailer ransack gem?

first part of question vital. should separate question.

unfortunately, there in no more elegant way cope it, than:

search(retailer_id_in: ([] + [-1])) 

the problem lays somewhere in gem. , if pass empty array, or array filled nil values parameter, there join in sql, conditions ignored, e.g.:

ruby:

article.ransack({authors_id_in: [nil, nil, nil]}).result 

sql:

select "articles".* "articles" left outer join "articles_authors" on "articles_authors"."article_id" = "articles"."id" left outer join "authors" on "authors"."id" = "articles_authors"."author_id" 

---

your second part of question searching through habtm relations using ransack, explained in rails 3.1 ransack habtm pretty good.

therefore:

promotion.ransack({retailer_id_in: [1,2,3]}).result 

you should not use promotionsretailer class itself.