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。

Microsoft Azure DocumentDB supports querying documents using SQL over JSON documents. You can sort documents in the collection on numbers and strings using an ORDER BY clause in your query. The clause can include an optional ASC/DESC argument to specify the order in which results must be retrieved.

让我们来看一下以下示例，在其中我们有一个 JSON 文档。

Let’s take a look at the following example in which we have a JSON document.

{
   "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。

Following is the SQL query to sort the result in a descending order.

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。

When the above query is executed, you will receive the following output.

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