DocumentDB – 排序记录

Microsoft Azure DocumentDB 支持使用 SQL over JSON 文档查询文档。您可以在查询中使用 ORDER BY 子句根据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 参数来指定必须检索结果的顺序。

让我们看一下以下示例，其中有一个 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
   }
]