我想算total no of Products
特定的購物清單,然後根據其在Shopping List table
。我的ID創建產品表如何計算一個表中的值,然後在另一個表中顯示相同的值?
我的購物清單表是一個和shopping_list參考顯示total count of products
該購物清單如下: -
id serial NOT NULL,
shopping_list_name character varying(255),
shopping_list_status character varying(255) DEFAULT 'OPEN'::character varying,
total_items character varying(255) DEFAULT 0,
created_at timestamp without time zone NOT NULL,
updated_at timestamp without time zone NOT NULL,
deleted integer NOT NULL DEFAULT 0,
CONSTRAINT shopping_lists_pkey PRIMARY KEY (id)
我的產品表如下: -
id serial NOT NULL,
shopping_list_id integer NOT NULL,
product_name character varying(255) DEFAULT 'null'::character varying,
product_category character varying(255),
quantity integer,
status character varying(255) DEFAULT 'OPEN'::character varying,
deleted integer NOT NULL DEFAULT 0,
CONSTRAINT products_pkey PRIMARY KEY (id)
誰能請幫我: -
聽起來像你只是想通過shopping.id從購物內連接產品(...)中選擇shopping.id,count(product.id),sum(product.quantity) – 2013-03-02 07:12:46
@CraigRinger這正是我想要做的。可以幫助你的細節 – Rockking 2013-03-02 12:47:19
這幾乎*是細節。如果你的意思是「你可以把它寫成一個ActiveRecord查詢」,那麼不,對不起,我不做ActiveRecord,但是你可以把它翻譯回SQL。 – 2013-03-02 18:19:49