如何在n1ql查询中检索父母的孩子答案

【问题标题】：how to retrieve the child of the parent in n1ql query如何在n1ql查询中检索父母的孩子
【发布时间】：2019-05-31 19:10:47
【问题描述】：

我计划根据某些条件检索父级的子元素。我如何检索它，在数组对象的数组中。

SELECT ARRAY {s.name,s.id} FOR s IN t.countryDetails.stateInfo END AS stateDetails
FROM test AS t 
WHERE t.type = "countries" and t.countryDetails.name = 'US';

这是我要查询的实际 json 文档：

{
   "type":"countries",
   "docName":"CountryData",
   "countryDetails":[
      {
         "name":"US",
         "code":"+1",
         "stateInfo":[
            {
               "name":"Florida",
               "id":"1212"
            },
            {
               "name":"NewYork",
               "id":"1214"
            }
         ]
      },
       {
         "name":"France",
         "code":"+33",
         "stateInfo":[
            {
               "name":"Grand Est",
               "id":"5212"
            },
            {
               "name":"Brittany",
               "id":"5214"
            }
         ]
      }
   ]
}

我希望以下输出仅显示美国的国家/地区详细信息：

[
            {
               "name":"Florida",
               "id":"1212"
            },
            {
               "name":"NewYork",
               "id":"1214"
            }
         ]

【问题讨论】：

标签： couchbase n1ql spring-data-couchbase

【解决方案1】：

如果您的 ConutryDetails 每个国家/地区只有一个条目，请使用以下

SELECT FIRST s.stateInfo FOR IN t.countryDetails WHEN s.name = "US" END AS stateDetails
FROM test AS t 
WHERE t.type = "countries" 
      AND ANY v IN t.countryDetails SATISFIES v.name = 'US' END;

或

SELECT cd.stateInfo AS stateDetails
FROM test AS t
UNNEST t.countryDetails AS cd
WHERE t.type = "countries" AND cd.name = 'US';

【讨论】：