弹性搜索:获取少数字段数据的计数

Question

[
{"Exam" : "mid-term 1", "Name": "abc", "Roll no" : "1" , "English" :"Pass", "Hindi" :"Pass" , "Physics" : "Not available", "Maths": "Fail"},
{"Exam" : "mid-term 2", "Name": "abc", "Roll no" : "1" , "English" :"Fail", "Hindi" :"Pass" , "Physics" : "Fail", "Maths": "result awaiting"},
{"Exam" : "mid-term 3", "Name": "abc", "Roll no" : "1" , "English" :"Pass", "Hindi" :"Fail" , "Physics" : "Pass", "Maths": "Pass"},

{"Exam" : "mid-term 1", "Name": "cde", "Roll no" : "2" , "English" :"Pass", "Hindi" :"Pass" , "Physics" : "Pass", "Maths": "Pass"},
{"Exam" : "mid-term 2", "Name": "cde", "Roll no" : "2" , "English" :"Pass", "Hindi" :"Pass" , "Physics" : "Pass", "Maths": "Pass"},
{"Exam" : "mid-term 3", "Name": "cde", "Roll no" : "2" , "English" :"Pass", "Hindi" :"Pass" , "Physics" : "Pass", "Maths": "Pass"},

{"Exam" : "mid-term 1", "Name": "xyz", "Roll no" : "3" , "English" :"Pass", "Hindi" :"Pass" , "Physics" : "Pass", "Maths": "Pass"},
{"Exam" : "mid-term 2", "Name": "xyz", "Roll no" : "3" , "English" :"result awaiting", "Hindi" :"Fail" , "Physics" : "Fail", "Maths": "Pass"},
{"Exam" : "mid-term 3", "Name": "xyz", "Roll no" : "3" , "English" :"Pass", "Hindi" :"Pass" , "Physics" : "Fail", "Maths": "Fail"},

{"Exam" : "mid-term 1", "Name": "zxc", "Roll no" : "4" , "English" :"Not available", "Hindi" :"result awaiting" , "Physics" : "Fail", "Maths": "Pass"},
{"Exam" : "mid-term 2", "Name": "zxc", "Roll no" : "4" , "English" :"Not available", "Hindi" :"Pass" , "Physics" : "Pass", "Maths": "Fail"},
{"Exam" : "mid-term 3", "Name": "zxc", "Roll no" : "4" , "English" :"Not available", "Hindi" :"Pass" , "Physics" : "Pass", "Maths": "Pass"},
]

假设我们有像上面这样的数据，有名字和Rollno以及主题及格的学生的三种不同的考试数据，失败/不可用(比如不尝试)，结果等待。

现在我们需要在物理不及格的基础上计算不同的字段，因此ROll no 1,2,4在物理考试中失败(在任何考试中都不及格，中期1/2 /3)，所以如果我们从物理失败中获取数据，它将如下所示

{"Exam" : "mid-term 3", "Name": "abc", "Roll no" : "1" , "English" :"Pass", "Hindi" :"Fail" , "Physics" : "Pass", "Maths": "Pass"},

{"Exam" : "mid-term 2", "Name": "xyz", "Roll no" : "3" , "English" :"Pass", "Hindi" :"Fail" , "Physics" : "Fail", "Maths": "Pass"},
{"Exam" : "mid-term 3", "Name": "xyz", "Roll no" : "3" , "English" :"Pass", "Hindi" :"Pass" , "Physics" : "Fail", "Maths": "Fail"},

{"Exam" : "mid-term 1", "Name": "zxc", "Roll no" : "4" , "English" :"Not available", "Hindi" :"result awaiting" , "Physics" : "Fail", "Maths": "Pass"},

但我不希望学生的数据只重复一次(不管考试)。

像下面的数据

{"Exam" : "mid-term 3", "Name": "abc", "Roll no" : "1" , "English" :"Pass", "Hindi" :"Fail" , "Physics" : "Pass", "Maths": "Pass"},

{"Exam" : "mid-term 2", "Name": "xyz", "Roll no" : "3" , "English" :"Pass", "Hindi" :"Fail" , "Physics" : "Fail", "Maths": "Pass"},

{"Exam" : "mid-term 1", "Name": "zxc", "Roll no" : "4" , "English" :"Not available", "Hindi" :"result awaiting" , "Physics" : "Fail", "Maths": "Pass"},

现在我要清点数据

English : 2 ( roll 1 annd 3 was pass , not condidered roll no 4 english due to Not available")

Hindi : 0 (no pass)
Physics: 1
Maths: 3

我们能在单个ES查询中实现此计数吗？

Answer 1

是的，在主题上使用术语聚合

{
  "aggs":{
    "english":{
      "terms": { "field": "english" }
    },
     "physics":{
      "terms": { "field": "physics" }
    },
     "hindi":{
      "terms": { "field": "hindi" }
    }
  }
}

结果会是这样的

  "aggs": {
    "english": [
      {
        "Pass": {
          "doc_count": 2
        }
      },
      {
        "Fail": {
          "doc_count": 1
        }
      },
      {
        "Not Available": {
          "doc_count": 3
        }
      }
    ]
  }
}```