我從我的鐵軌控制檯打下面的查詢採摘:分別選擇和軌道擊中同一個SQL查詢,但有不同的結果
Listing.joins(:colors, :sizes, :product, :orders).pluck('colors.id', 'sizes.id', 'products.id', 'orders.id')
(4.5ms) SELECT colors.id, sizes.id, products.id, orders.id FROM "listings" INNER JOIN "colors" ON "colors"."listing_id" = "listings"."id" INNER JOIN "sizes" ON "sizes"."listing_id" = "listings"."id" INNER JOIN "products" ON "products"."id" = "listings"."product_id" INNER JOIN "orders" ON "orders"."listing_id" = "listings"."id"
和
Listing.joins(:colors, :sizes, :product, :orders).select('colors.id', 'sizes.id', 'products.id', 'orders.id')
Listing Load (4.6ms) SELECT colors.id, sizes.id, products.id, orders.id FROM "listings" INNER JOIN "colors" ON "colors"."listing_id" = "listings"."id" INNER JOIN "sizes" ON "sizes"."listing_id" = "listings"."id" INNER JOIN "products" ON "products"."id" = "listings"."product_id" INNER JOIN "orders" ON "orders"."listing_id" = "listings"."id"
,並得到了以下結果:
[[2, 3, 1, 1], [2, 3, 1, 2], [2, 2, 1, 1], [2, 2, 1, 2], [2, 1, 1, 1], [2, 1, 1, 2], [3, 3, 1, 1], [3, 3, 1, 2], [3, 2, 1, 1], [3, 2, 1, 2], [3, 1, 1, 1], [3, 1, 1, 2], [4, 3, 1, 1], [4, 3, 1, 2], [4, 2, 1, 1], [4, 2, 1, 2], [4, 1, 1, 1], [4, 1, 1, 2]]
和
#<ActiveRecord::Relation [#<Listing id: 1>, #<Listing id: 2>, #<Listing id: 1>, #<Listing id: 2>, #<Listing id: 1>, #<Listing id: 2>, #<Listing id: 1>, #<Listing id: 2>, #<Listing id: 1>, #<Listing id: 2>, ...]>
請幫忙,這對我來說很安靜。
普呂克返回一個數組中,選擇返回對象,在這種情況下,一些信息 –