如何使用go在弹性搜索中按嵌套对象对文档进行排序？

Question

I'm new to Elasticsearch.

I have documents and each of them has a structure like this:

{
    "created_at": "2018-01-01 01:01:01",
    "student": {
        "first_name": "john",
        "last_name": "doe"
    },
    "parent": {
        "first_name": "susan",
        "last_name": "smile"
    }
}

I just want to sort those documents based on student.first_name using olivere/elastic package for go.

This is my query at the moment:

searchSvc = searchSvc.SortBy(elastic.NewFieldSort("student.first_name").Asc())

and I'm getting this error:

elastic: Error 400 (Bad Request): all shards failed [type=search_phase_execution_exception]

However when I tried sorting it by created_at, it's working.

searchSvc = searchSvc.SortBy(elastic.NewFieldSort("created_at").Asc())

I don't have any mapping in the index. (is this the problem?)

I tried searching for something like "Elasticsearch sort by nested object", but I always got questions that need to sort an array in the nested object.

Answer 1

It turns out that this is a beginner mistake.. You can't sort by text fields. I got it from here elasticsearch-dsl-py Sorting by Text() field

What you can do though, if you don't specify mappings, you can sort by the keyword property of the field.

searchSvc = searchSvc.SortBy(elastic.NewFieldSort("student.first_name.keyword").Asc())

And it works!