Question

我有三张桌子：

product:
    id
    name

product_image:
    product_id
    url

product_detail:
    product_id
    _key
    value

我想要做的就是在一个查询中获取有关特定产品的所有信息。我正在获取group_concatenated图像和细节，但我有分组问题（我想是这样）。有时我会得到双倍的图像。我的疑问是：

   SELECT p.id, p.name,
GROUP_CONCAT(i.url ORDER BY i.id ASC SEPARATOR "{^sep^}") as imgs,
GROUP_CONCAT(d._key, "{^val^}", d.value ORDER BY d.id asc separator "{^sep^}") AS details
FROM product p
LEFT JOIN product_image i ON p.id = i.product_id
LEFT JOIN product_detail d ON p.id = d.product_id
WHERE p.id = ...
GROUP BY i.product_id, d.product_id 
ORDER BY p.id ASC LIMIT ...;

而且，顺便说一下，我使用“{^ sep ^}”作为分隔符，以便稍后在（在php中）爆炸结果。我想确定，url（和细节）不会以错误的方式爆炸（例如，如果我使用'，'作为分隔符，而某些URL也包含'，'）。这是一个好方法吗？

Answer 1

您应该按p.id和p.name进行分组。您也可以使用DISTINCT：

SELECT p.id, p.name,
GROUP_CONCAT(i.url ORDER BY i.id ASC SEPARATOR "{^sep^}") as imgs,
GROUP_CONCAT(d._key, "{^val^}", d.value ORDER BY d.id asc separator "{^sep^}") AS details
FROM product p
LEFT JOIN product_image i ON p.id = i.product_id
LEFT JOIN product_detail d ON p.id = d.product_id
WHERE p.id = ...
GROUP BY p.id, p.name
ORDER BY p.id ASC LIMIT ...;

或

SELECT DISTINCT p.id, p.name,
GROUP_CONCAT(i.url ORDER BY i.id ASC SEPARATOR "{^sep^}") as imgs,
GROUP_CONCAT(d._key, "{^val^}", d.value ORDER BY d.id asc separator "{^sep^}") AS details
FROM product p
LEFT JOIN product_image i ON p.id = i.product_id
LEFT JOIN product_detail d ON p.id = d.product_id
WHERE p.id = ...
GROUP BY i.product_id, d.product_id 
ORDER BY p.id ASC LIMIT ...;

SQL很多加入分组

1 个答案: