Question

我有3个数据库表，我需要信息来自。我需要的信息是缩进的。

--products 
    --product_image
--order_options 
    --option_value
--order_products
    --product_id

现在我有以下代码

foreach ($db->query("SELECT * FROM products WHERE product_id= $product_id") as $row)
    order_product[] = $row;

foreach ($db->query("SELECT * FROM order_options WHERE order_id= $order_id") as $row)
    order_size[] = $row;

foreach ($db->query("SELECT * FROM order_products WHERE order_id= $order_id") as $row)
    order_source[] = $row;

（order_id来自脚本中的$order_id = $_GET['id'];。）

我想将所有三个select语句放在一个查询中。我已经看到了这一点，但从来没有真正理解我找到的任何东西（即an old question from this site）我理解youtube video我看过并设法将上述内容更改为以下内容：

foreach ($db->query("SELECT * FROM [order_products] as opro INNER JOIN order_options as oopt ON opro.order_id = oopt.order_id") as $row)
        $order_variables[] = $row;

虽然我运行时遇到此错误：

Warning: Invalid argument supplied for foreach() in /home/www/libraries/phppwinty/print.php on line 35

那么如何在这些JOIN表之间取得成功3？

Answer 1

这样的事情应该有效。想法：按照product_id加入产品，order_id加入order_options，并在指定的ID上加上order_products：

SELECT orderproducts.product_id, orderoptions.option_value, products.product_image

FROM order_products as orderproducts

INNER JOIN order_options as orderoptions ON orderproducts.order_id = orderoptions.order_id
INNER JOIN products as products ON orderproducts.product_id = products.product_id

WHERE 
orderproducts.order_id = $order_id AND
orderproducts.product_id = $product_id

用PHP连接3个数据库表

1 个答案: