# Top k of top n: best way to do a nested aggregation

**URL:** <https://discuss.elastic.co/t/top-k-of-top-n-best-way-to-do-a-nested-aggregation/19664>\
**Category:** Elasticsearch\
**Created:** [September 8, 2014, 7:03pm UTC](https://discuss.elastic.co/t/top-k-of-top-n-best-way-to-do-a-nested-aggregation/19664 "2014-09-08T19:03:25Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![geantbrun](https://avatars.discourse-cdn.com/v4/letter/g/ecb155/32.png) [@geantbrun](https://discuss.elastic.co/u/geantbrun)\
**Post date:** [September 8, 2014, 7:03pm UTC](https://discuss.elastic.co/t/top-k-of-top-n-best-way-to-do-a-nested-aggregation/19664/1 "2014-09-08T19:03:25Z")

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Hi,  
I have millions of documents that contain (among others) two fields:  
property1 and property2. Each of these fields can take many values in each  
document. Suppose now that I want to list the top n values of property1 and  
for each of these values, find the top k values of property2. For example,  
the result of the top 2 of prop.2 for each of the top 3 of prop.1 could be:

prop1: YELLOW  
prop2: heavyweight  
prop2: useful

prop1: RED  
prop2: unuseful  
prop2: lightweight

prop1: BLACK  
prop2: handy  
prop2: lightweight

My first try with aggregations is:

{  
"size": 0,  
"aggs" : {  
"topn" : {  
"terms" : { "field" : "property1" , "size":3},  
"aggs": {  
"topk":{  
"terms":{"field":"property2","size":2}  
}  
}  
}  
}  
}

First: is it correct? Second: is is the best way to do it?  
My guesses are yes and no.  
Any help is appreciated.

Regards,  
Patrick

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 6, 2017, 1:03am UTC](https://discuss.elastic.co/t/top-k-of-top-n-best-way-to-do-a-nested-aggregation/19664/2 "2017-07-06T01:03:51Z")

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