DocumentDB SQL - 陣列建立

在 DocumentDB SQL 中，Microsoft 添加了一個關鍵功能，我們可藉助它輕鬆建立陣列。這表示當我們執行查詢時，作為查詢結果，它將建立一個類似於 JSON 物件的集合陣列。

讓我們考慮與之前示例中相同的文件。

AndersenFamily 文件如下。

{ 
   "id": "AndersenFamily", 
   "lastName": "Andersen",
	
   "parents": [ 
      { "firstName": "Thomas", "relationship":  "father" }, 
      { "firstName": "Mary Kay", "relationship":  "mother" } 
   ], 
   
   "children": [ 
      { 
         "firstName": "Henriette Thaulow", 
         "gender": "female", 
         "grade": 5, 
         "pets": [ { "givenName": "Fluffy", "type":  "Rabbit" } ] 
      } 
   ],
   
   "location": { "state": "WA", "county": "King", "city": "Seattle" }, 
   "isRegistered": true 
} 

SmithFamily 文件如下。

{ 
   "id": "SmithFamily", 
	
   "parents": [ 
      { "familyName": "Smith", "givenName": "James" }, 
      { "familyName": "Curtis", "givenName": "Helen" } 
   ],
   
   "children": [ 
      {
         "givenName": "Michelle", 
         "gender": "female", 
         "grade": 1 
      },
		
      { 
         "givenName": "John", 
         "gender": "male", 
         "grade": 7,
			
         "pets": [ 
            { "givenName": "Tweetie", "type": "Bird" } 
         ] 
      } 
   ], 
   
   "location": { 
      "state": "NY", 
      "county": "Queens", 
      "city": "Forest Hills" 
   },
   
   "isRegistered": true 
}

WakefieldFamily 文件如下。

{ 
   "id": "WakefieldFamily", 
	
   "parents": [ 
      { "familyName": "Wakefield", "givenName": "Robin" }, 
      { "familyName": "Miller", "givenName": "Ben" } 
   ],
   
   "children": [ 
      { 
         "familyName": "Merriam", 
         "givenName": "Jesse", 
         "gender": "female", 
         "grade": 6,
			
         "pets": [ 
            { "givenName": "Charlie Brown", "type": "Dog" }, 
            { "givenName": "Tiger", "type": "Cat" }, 
            { "givenName": "Princess", "type": "Cat" }
         ]
      },
		
      { 
         "familyName": "Miller", 
         "givenName": "Lisa", 
         "gender": "female", 
         "grade": 3,
			
         "pets": [ 
            { "givenName": "Jake", "type": "Snake" } 
         ] 
      } 
   ], 
   
   "location": { "state": "NY", "county": "Manhattan", "city": "NY" }, 
   "isRegistered": false 
}

我們來看一個示例。

下文是一個查詢，它將返回每個家庭的家庭名稱和地址。

SELECT f.id AS FamilyName, 
[f.location.city, f.location.county, f.location.state] AS Address 
FROM Families f

正如你所見，city、county 和 state 欄位包含在方括號中，這將建立一個數組，此陣列名為 Address。當執行上述查詢時，它產生以下輸出。

[ 
   { 
      "FamilyName": "WakefieldFamily", 
      "Address": [ 
         "NY", 
         "Manhattan", 
         "NY" 
      ] 
   },
	
   { 
      "FamilyName": "SmithFamily", 
      "Address": [
         "Forest Hills", 
         "Queens", 
         "NY" 
      ] 
   },
	
   { 
      "FamilyName": "AndersenFamily", 
      "Address": [ 
         "Seattle", 
         "King", 
         "WA" 
      ] 
   } 
]

city、county 和 state 資訊已新增到上述輸出中的 Address 陣列。