php - 在 Android 中从两个表中检索没有重复的数据？

Question

我使用以下 sql 语句从两个不同的表中提取数据:

    $query=mysqli_query($con,"SELECT products.pid,products.product_name,products.product_pic,products.product_thumb,products.product_description,products.product_rating,comments.username, comments.comment FROM products RIGHT JOIN comments on products.pid = comments.pid");

我试过:

LEFT JOIN
INNER JOIN
AND JUST JOIN

不幸的是，在 Android ListView 中，如果产品有多个评论，我会得到重复的结果。像这样:

        {
            "pid": "2",
            "product_name": "Some product one",
            "product_pic": "http://localhost/img/generic.png",
            "product_thumb": "",
            "product_description": "some long description",
            "product_rating": "0",
            "username": "john",
            "comment": "one of my favorites"
        },
        {
            "pid": "2",
            "product_name": "Some product one",
            "product_pic": "http://localhost/img/generic.png",
            "product_thumb": "",
            "product_description": "some long description",
            "product_rating": "0",
            "username": "jane",
            "comment": "this was so cool"
        }

如何让 JSON 结果显示在一行中而不是复制产品？

Answer 1

您对 SQL 请求的确切期望是什么？

你想要这样的东西吗？

{
    "pid": "2",
    "product_name": "Some product one",
    "product_pic": "http://localhost/img/generic.png",
    "product_thumb": "",
    "product_description": "some long description",
    "product_rating": "0",
    "comments" : [
        {
            "username": "john",
            "comment": "one of my favorites"
        },
        {
            "username": "jane",
            "comment": "this was so cool"
        }
    ]
}

这对于 SQL 是不可能的，但是您可以将 SQL 响应更改为这种格式。另一种选择是先请求产品，然后调用第二个评论请求。