来自3个表的SQL查询，无法获得所需的结果

Question

- 列出与艺术家，订单日期和发货日期一起出售的所有商品

SELECT title, artist, order_date, ship_date
FROM items,orders,orderline
WHERE orders.order_id = orderline.order_id
AND items.item_id = orderline.item_id;

我尝试了自己的查询，我得到了以下结果

Under the Sun, Donald Arley, 11/15/2013, 11/20/2013

Under the Sun, Donald Arley, 12/20/2013, 12/22/2013

Under the Sun, Donald Arley, 1/18/2014, 1/23/2014

Dark Lady, Keith Morris, 1/31/2014, 2/4/2014

Dark Lady, Keith Morris, 3/10/2014, 3/15/2014

Dark Lady, Keith Morris, 3/14/2014, 3/19/2014

Dark Lady, Keith Morris, 11/15/2013, 11/20/2013

Happy Days, Andrea Reid, 2/27/2014, 3/2/2014

Happy Days, Andrea Reid, 10/30/2013, 11/3/2013

Happy Days, Andrea Reid, 12/18/2013, 12/22/2013

The Hunt, Walter  Alford, 1/31/2014, 2/4/2014

The Hunt, Walter  Alford, 3/10/2014, 3/15/2014

等...............

Answer 1

这看起来像是一个通用的家庭作业问题。

我建议您熟悉此页面和网站http://use-the-index-luke.com/sql/join。

解决方案：

将您的陈述更改为：

SELECT 
    items.title, items.artist, orders.order_date, orders.ship_date
FROM 
    items 
JOIN 
    orderline ON orderline.item_id = items.item_id 
JOIN 
    orders ON orders.order_id = orderline.order_id