How to do joins and grouping in Ecto

I know this can be achieved using raw SQL and Ecto.Adapters.SQL.query() but what is the Ecto way to it? Any help is highly appreciated, thank you.

SELECT COUNT(*) AS count, products.name AS product, categories.name AS category, stores.name AS store FROM "items"
  INNER JOIN "stores" ON "stores"."id" = "items"."store_id"
  INNER JOIN "products" ON "products"."id" = "items"."product_id"
  INNER JOIN "categories" ON "categories"."id" = "products"."category_id"
  WHERE "items"."store_id" IN (#{store_ids}) AND "items"."product_id"
		IN (#{product_ids}) AND (products.category_id IN (#{category_ids}))
  GROUP BY products.name, categories.name, stores.name
  ORDER BY products.name