azure-cosmosdb - Azure DocumentDb中数组上的WHERE子句

Question

在这样的Azure Documentdb文档中

{
"id": "WakefieldFamily",
"parents": [
    { "familyName": "Wakefield", "givenName": "Robin" },
    { "familyName": "Miller", "givenName": "Ben" }
],
"children": [
    {
        "familyName": "Merriam", 
        "givenName": "Jesse", 
        "gender": "female", 
        "grade": 1,
        "pets": [
            { "givenName": "Goofy" },
            { "givenName": "Shadow" }
        ]
    },
    { 
      "familyName": "Miller", 
      "givenName": "Lisa", 
      "gender": "female", 
      "grade": 8 
    }
],
  "address": { "state": "NY", "county": "Manhattan", "city": "NY" },
  "isRegistered": false
};

如何查询让宠物叫“高飞”的 child ？

看起来以下语法无效

Select * from root r
WHERE r.children.pets.givenName="Goofy"

相反，我需要做

Select * from root r
WHERE r.children[0].pets[0].givenName="Goofy"

并不是真正在数组中搜索。

关于如何处理此类查询的任何建议？

Answer 1

您应该利用DocumentDB的JOIN子句，该子句的操作与RDBM中的JOIN有所不同(因为DocumentDB处理的是无模式文档的去 ionic 化数据模型)。

简而言之，您可以将DocumentDB的JOIN视为自连接，可用于在嵌套JSON对象之间形成交叉乘积。

在查询宠物名为“高飞”的 child 时，可以尝试:

SELECT 
    f.id AS familyName,
    c AS child,
    p.givenName AS petName 
FROM Families f 
JOIN c IN f.children 
JOIN p IN c.pets
WHERE p.givenName = "Goofy"

哪个返回:

[{
    familyName: WakefieldFamily,
    child: {
        familyName: Merriam,
        givenName: Jesse,
        gender: female,
        grade: 1,
        pets: [{
            givenName: Goofy
        }, {
            givenName: Shadow
        }]
    },
    petName: Goofy
}]

引用: http://azure.microsoft.com/en-us/documentation/articles/documentdb-sql-query/

编辑:

您还可以使用 ARRAY_CONTAINS函数，该函数如下所示:

SELECT food.id, food.description, food.tags
FROM food
WHERE food.id = "09052" or ARRAY_CONTAINS(food.tags.name, "blueberries")