聚合 couchbase 文档数据

【问题标题】：Aggregate the couchbase document Data聚合 couchbase 文档数据
【发布时间】：2019-03-15 04:42:13
【问题描述】：

在 couchbase 中，是否有任何聚合方法或模板（没有 N1QL）用于聚合值？

我的 couchbase 文档遵循以下格式：

{"Students":[
    {
    "Student_id": "101",
    "Name": "Jon",
    "Course" : "Engineer"
    },
    {
    "Student_id": "102",
    "Name": "Snow",
    "Course" : "Medical"
    },
    {
    "Student_id": "103",
    "Name": "Walter",
    "Course" : "Chemistry"
    },
    {
    "Student_id": "104",
    "Name": "White",
    "Course" : "Chemistry"
    }]}

【问题讨论】：

标签： couchbase

【解决方案1】：

您可以按如下方式使用 N1QL。

INSERT INTO default VALUES("f001",{"Students":[ { "Student_id": "101", "Name": "Jon", "Course" : "Engineer" }, { "Student_id": "102", "Name": "Snow", "Course" : "Medical" }, { "Student_id": "103", "Name": "Walter", "Course" : "Chemistry" }, { "Student_id": "104", "Name": "White", "Course" : "Chemistry" } ] } );

SELECT (OBJECT v.Course||"Students":v.cnt
       FOR v IN ARRAY_APPEND(ds, {"Course":"", "cnt": ARRAY_SUM(ds[*].cnt)})
       END).*
LET ds = (SELECT s.Course|| " " AS Course , COUNT(1) AS cnt
           FROM default AS d
           UNNEST d.Students AS s
           GROUP BY s.Course);

【讨论】：