Documentdb 简明教程

DocumentDB - Sorting Records

Microsoft Azure DocumentDB 支持使用 JSON 文档中的 SQL 查询文档。您可以使用查询中的 ORDER BY 子句按照数字和字符串对集合中的文档进行排序。该子句可以包含一个可选的 ASC/DESC 参数，以指定必须检索结果的顺序。

让我们来看一下以下示例，在其中我们有一个 JSON 文档。

{
   "id": "Food Menu",
   "description": "Grapes, red or green (European type, such as Thompson seedless), raw",

   "tags": [
      {
         "name": "grapes"
      },

      {
         "name": "red or green (european type"
      },

      {
         "name": "such as thompson seedless)"
      },

      {
         "name": "raw"
      }
   ],

   "foodGroup": "Fruits and Fruit Juices",

   "servings": [
      {
         "amount": 1,
         "description": "cup",
         "weightInGrams": 151
      },

      {
         "amount": 10,
         "description": "grapes",
         "weightInGrams": 49
      },

      {
         "amount": 1,
         "description": "NLEA serving",
         "weightInGrams": 126
      }
   ]

}

以下是按降序对结果进行排序的 SQL 查询。

SELECT f.description, f.foodGroup,
   f.servings[2].description AS servingDescription,
   f.servings[2].weightInGrams AS servingWeight

FROM f
ORDER BY f.servings[2].weightInGrams DESC

执行上述查询时，您将收到以下输出。

[
   {
      "description": "Grapes, red or green (European type, such as Thompson
         seedless), raw",
      "foodGroup": "Fruits and Fruit Juices",
      "servingDescription": "NLEA serving",
      "servingWeight": 126
   }
]