此问题很复杂，我需要通过sql查询来查找尚未购买产品的客户，product_id和价格

Question

sql查询以列出数据库中任何客户未购买产品的所有产品的ID，名称和价格。该清单必须按产品价格订购。注意：order_items中的单价是产品的价格。

我已经列出了上述问题所需的表格。

CREATE TABLE products
  (
    product_id NUMBER 
               GENERATED BY DEFAULT AS IDENTITY START WITH 289 
               PRIMARY KEY,
    product_name  VARCHAR2( 255 ) NOT NULL,
    description   VARCHAR2( 2000 )        ,
    standard_cost NUMBER( 9, 2 )          ,
    list_price    NUMBER( 9, 2 )          ,
    category_id   NUMBER NOT NULL         ,
    CONSTRAINT fk_products_categories 
      FOREIGN KEY( category_id )
      REFERENCES product_categories( category_id ) 
      ON DELETE CASCADE
  );
-- customers
CREATE TABLE customers
  (
    customer_id NUMBER 
                GENERATED BY DEFAULT AS IDENTITY START WITH 320 
                PRIMARY KEY,
    name         VARCHAR2( 255 ) NOT NULL,
    address      VARCHAR2( 255 )         ,
    website      VARCHAR2( 255 )         ,
    credit_limit NUMBER( 8, 2 )
  );
-- contacts
CREATE TABLE contacts
  (
    contact_id NUMBER 
               GENERATED BY DEFAULT AS IDENTITY START WITH 320 
               PRIMARY KEY,
    first_name  VARCHAR2( 255 ) NOT NULL,
    last_name   VARCHAR2( 255 ) NOT NULL,
    email       VARCHAR2( 255 ) NOT NULL,
    phone       VARCHAR2( 20 )          ,
    customer_id NUMBER                  ,
    CONSTRAINT fk_contacts_customers 
      FOREIGN KEY( customer_id )
      REFERENCES customers( customer_id ) 
      ON DELETE CASCADE
  );
-- orders table
CREATE TABLE orders
  (
    order_id NUMBER 
             GENERATED BY DEFAULT AS IDENTITY START WITH 106 
             PRIMARY KEY,
    customer_id NUMBER( 6, 0 ) NOT NULL, -- fk
    status      VARCHAR( 20 ) NOT NULL ,
    salesman_id NUMBER( 6, 0 )         , -- fk
    order_date  DATE NOT NULL          ,
    CONSTRAINT fk_orders_customers 
      FOREIGN KEY( customer_id )
      REFERENCES customers( customer_id )
      ON DELETE CASCADE,
    CONSTRAINT fk_orders_employees 
      FOREIGN KEY( salesman_id )
      REFERENCES employees( employee_id ) 
      ON DELETE SET NULL
  );
-- order items
CREATE TABLE order_items
  (
    order_id   NUMBER( 12, 0 )                                , -- fk
    item_id    NUMBER( 12, 0 )                                ,
    product_id NUMBER( 12, 0 ) NOT NULL                       , -- fk
    quantity   NUMBER( 8, 2 ) NOT NULL                        ,
    unit_price NUMBER( 8, 2 ) NOT NULL                        ,
    CONSTRAINT pk_order_items 
      PRIMARY KEY( order_id, item_id ),
    CONSTRAINT fk_order_items_products 
      FOREIGN KEY( product_id )
      REFERENCES products( product_id ) 
      ON DELETE CASCADE,
    CONSTRAINT fk_order_items_orders 
      FOREIGN KEY( order_id )
      REFERENCES orders( order_id ) 
      ON DELETE CASCADE
  );

Answer 1

这里是示例查询：

SELECT P.product_id, P.product_name, P.list_price FROM products AS P LEFT JOIN order_items AS OI ON P.product_id = OI.product_id
WHERE OI.product_id IS NULL;

我希望这对您有用或对您有所帮助！