MySQL 查询以获取产品变型

MySQL query to fetch product variants

我正在尝试获取产品变体属性以显示在产品页面上。我想要以下输出:

color: red (size: S, M), green (size: S)

但我得到:

color: red, green size: S, M

这是我目前拥有的简化版本:

 产品 TABLE
|编号 |
--------------
| 1 |
| 1 |
| 1 |
 变体 TABLE
|编号 |fk_product_id|
--------------------------
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
 属性 TABLE
|fk_variant_id| 属性 |价值 |
--------------------------------------
| 1 |颜色 |红色 |
| 1 |尺码 |年代 |
| 2 |颜色 |绿色 |
| 2 |尺码 |年代 |
| 3 |颜色 |红色 |
| 3 |尺码 |男|
$stmt=$db->prepare('SELECT
    attribute.property AS property,
    GROUP_CONCAT(DISTINCT attribute.value) AS value
FROM product
INNER JOIN variant
    ON product.id=variant.fk_product_id
LEFT JOIN attribute
    ON variant.id=attribute.fk_variant_id
WHERE product_id=:product_id
GROUP BY attribute.property');

$stmt->bindParam(':product_id',$product_id);
$stmt->execute();
$query=$stmt->fetchAll();
foreach($query as $row){
  echo $row['property'].' '.$row['value'].'<br>';
}

最后的游戏是这样的:

此查询应该会为您提供所需的结果。它有效地创建了每个属性(colorsize)的表,并将它们连接到产品和变体。

SELECT p.id AS product, c.value AS color, GROUP_CONCAT(s.value) AS sizes
FROM product p
JOIN variant v ON v.fk_product_id = p.id
LEFT JOIN attribute c ON c.fk_variant_id = v.id AND c.property = 'color'
LEFT JOIN attribute s ON s.fk_variant_id = v.id AND s.property = 'size'
GROUP BY product, color

输出

product     color   sizes
1           green   S
1           red     S,M

Demo on dbfiddle