Question

我尝试列出所有带有产品图片的产品，但不确定如何在这种情况下使用subquery。以下是我的数据库结构

产品

products_id + product_name +
    1       |    Apple     |
    2       |    Banana    |

products_screenshot

products_id +       images       +
    1       |    Apple-1.jpg     |
    1       |    Apple-2.jpg     |
    1       |    Apple-3.jpg     |
    2       |    Banana-1.jpg    |
    2       |    Banana-2.jpg    |
    2       |    Banana-3.jpg    |

这是我的疑问：

$sql = "SELECT p.* FROM `products` p ORDER BY p.products_id ASC ";

//LEFT JOIN (SELECT ps.* FROM `products_screenshot` ps WHERE ps.products_id=p.products_id) AS pss ON(p.products_id=pss.products_id)

$query = $db->query($sql);

while ($row = $query->fetch_object()) {

     // result
     echo $row->products_name.'</br>';

     // list all product screenshot related with this 
     //$row->images

}

Answer 1

根据您的要求，您可以执行以下操作。然后执行查询并循环。该 $ row-＆gt;图片将以逗号分隔，您可以拆分它们以显示产品。

$sql = "SELECT p.products_id,p.product_name,group_concat(pi.images) as `images`
FROM `products` p 
left join products_screenshot  pi on pi.products_id = p.products_id
group by p.products_id
ORDER BY p.products_id ";

如果您不关心在循环中多次重复的产品，那么只需使用下面的每个循环的位置，您将获得产品和相关图像的新行

$sql = "SELECT p.products_id,p.product_name,pi.images
FROM `products` p 
left join products_screenshot  pi on pi.products_id = p.products_id
ORDER BY p.products_id ";

Answer 2

像这样的简单查询出了什么问题：

select
    p.products_id,
    p.product_name,
    ps.images
from
    products p
        join products_screenshot ps
            on p.products_id=ps.products_id
where
    whateveryouline
order by
    1,2

它能为您提供所需的所有物品吗？

Answer 3

尝试此查询：

select products.product_name, products_screenshot.images from products,products_screenshot  where products.products_id = products_screenshot.products_id

Answer 4

SELECT * from products_screenshot as ps where products_id IN (SELECT p.products_id from products as p WHERE p.products_id = ps.products_id )

选择带子查询的表

4 个答案: