Documentdb Sql 简明教程

DocumentDB SQL - Between Keyword

BETWEEN 关键字用于针对 SQL 中的如同值范围的查询进行表达。BETWEEN 可用于字符串或数字。在 DocumentDB 和 ANSI SQL 中使用 BETWEEN 的主要区别在于，您可以在混合类型的属性上表达范围查询。

例如，在某些文档中，您可能将“grade”作为数字，而在其他文档中它可能是字符串。在这些情况下，“未定义”两种不同类型的结果之间的比较，并且该文档将被跳过。

我们来考虑先前示例中的三个文档。以下是 AndersenFamily 文档。

{
   "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
}

以下是 SmithFamily 文档。

{
   "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
}

以下是 WakefieldFamily 文档。

{
   "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
}

我们来通过一个示例了解一下，其中该查询返回所有第一个孩子的成绩介于 1-5（包括边界）的家庭文档。

以下是使用 BETWEEN 关键字并随后使用 AND 逻辑运算符的查询。

SELECT *
FROM Families.children[0] c
WHERE c.grade BETWEEN 1 AND 5

执行以上查询后，将产生以下输出。

[
   {
      "givenName": "Michelle",
      "gender": "female",
      "grade": 1
   },

   {
      "firstName": "Henriette Thaulow",
      "gender": "female",
      "grade": 5,

      "pets": [
         {
            "givenName": "Fluffy",
            "type": "Rabbit"
         }
      ]
   }
]

要显示超出先前示例范围的成绩，请如以下查询所示使用 NOT BETWEEN。

SELECT *
FROM Families.children[0] c
WHERE c.grade NOT BETWEEN 1 AND 5

执行此查询时。它生成以下输出。

[
   {
      "familyName": "Merriam",
      "givenName": "Jesse",
      "gender": "female",
      "grade": 6,

      "pets": [
         {
            "givenName": "Charlie Brown",
            "type": "Dog"
         },

         {
            "givenName": "Tiger",
            "type": "Cat"
         },

         {
            "givenName": "Princess",
            "type": "Cat"
         }
      ]
   }
]