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POActiveRecord & PostgreSQL ordering error
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copied!<p>I have two models in my Rails app: Product and CardItem</p> <p>Product has field <em>price</em></p> <p>CardItem has field <em>quantity</em> and belongs to Product.</p> <p>I want to select total price of all card items depending on product.price * quantity</p> <pre><code>class CardItem < ActiveRecord::Base belongs_to :product scope :total_price, -> { result = joins(:product).select('SUM(products.price * card_items.quantity) as total_price') result.empty? ? 0 : result.first.total_price } end </code></pre> <p>This code perfectly works in sqlite, but with postgresql it throws error:</p> <pre><code>PG::GroupingError: ERROR: column "card_items.id" must appear in the GROUP BY clause or be used in an aggregate function LINE 1: ...t_id" WHERE "card_items"."user_id" = $1 ORDER BY "card_item... ^ : SELECT SUM(products.price * card_items.quantity) as total_price FROM "card_items" INNER JOIN "products" ON "products"."id" = "card_items"."product_id" WHERE "card_items"."user_id" = $1 ORDER BY "card_items"."id" ASC LIMIT 1 ActiveRecord::StatementInvalid: PG::GroupingError: ERROR: column "card_items.id" must appear in the GROUP BY clause or be used in an aggregate function LINE 1: ...t_id" WHERE "card_items"."user_id" = $1 ORDER BY "card_item... ^ : SELECT SUM(products.price * card_items.quantity) as total_price FROM "card_items" INNER JOIN "products" ON "products"."id" = "card_items"."product_id" WHERE "card_items"."user_id" = $1 ORDER BY "card_items"."id" ASC LIMIT 1 </code></pre> <p>help my fix this please </p> <p>p.s. I use Rails 4.0.0</p>

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