javascript - 使用 JSON 格式的 Node.JS 从 MySQL 中检索数据

Question

我有以下 MySQL 表:

| category | icon |
-------------------
| CAT_A    | xxx  |
| CAT_B    | yyy  |

和

| sub_category | icon | category
--------------------------------
| SUB_X        | ppp  | CAT_A
| SUB_Y        | qqq  | CAT_A
| SUB_Z        | rrr  | CAT_B
| SUB_U        | www  | CAT_B

现在我想在一个查询中获取所有数据我正在使用 Node.JS 并编写了以下查询

SELECT c.category categoryTitle, c.icon categoryIcon, s.sub_category subCategoryTitle, s.icon subCategoryIcon FROM categories c INNER JOIN sub_categories s ON c.title = s.category

这是我的 Node.JS 代码

var arrCategories = [];
    for (var category in rows) {
         if (rows.hasOwnProperty(category))
             arrCategories.push(rows[category]);
    }
    response.json(arrCategories);

现在我得到以下响应

[
{
  "categoryTitle":"CAT_A",
  "categoryIcon":"xxx",
  "subCategoryTitle":"SUB_X",
  "subCategoryIcon":"ppp"
},
{
  "categoryTitle":"CAT_A",
  "categoryIcon":"xxx",
  "subCategoryTitle":"SUB_Y",
  "subCategoryIcon":"qqq"
},......
]

但我想要以下输出:

[
{
  "categoryTitle":"CAT_A",
  "categoryIcon":"xxx",
  "subCategory":[
      {
         "subCategoryTitle":"SUB_X",
         "subCategoryIcon":"ppp"
      },
      {
         "subCategoryTitle":"SUB_Y",
         "subCategoryIcon":"qqq"
      },
   ]
},......
]

我应该怎么做才能获得所需格式的输出

需要任何帮助

Answer 1

这是另一个不需要更改 SQL 的选项。

var categoryMap = {};
var categories = [];
rows.forEach(function(row) {
   var category = categoryMap[row.categoryTitle];
   if (!category) {
      category = {
         categoryTitle: row.categoryTitle,
         categoryIcon: row.categoryIcon,
         subCategory: []
      };

      categoryMap[row.categoryTitle] = category;
      categories.push(category);
   }

   category.subCategory.push({
     subCategoryTitle: row.subCategoryTitle,
     subCategoryIcon: row.subCategoryIcon
   });
});

response.json(categories);