19.COUNT() , AVG() 聚合函数

在下边的例子我们使用COUNT()函数来告诉我们有多少文档在桶里。

COUNT() Query:

SELECT COUNT(*) AS count
    FROM tutorial

结果:

{
  "results": [
    {
      "count": 6
    }
  ]
}

AVG() Query:

SELECT COUNT(*) AS count, AVG(c.age) AS avg_age
FROM tutorial t
UNNEST t.children c
WHERE c.age > 10

结果：

{
  "results": [
    {
      "avg_age": 18,
      "count": 4
    }
  ]
}