Elastic Search text field aggregations

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1

Is there anyway possible to find min or max aggregation on text fields when we group by some fields

2

It would help if you provided an example of what you are looking for here as it is not entirely clear. What is mix and max in the context of a text field?

3

I have Employee table with name and department as columns.

I am trying to group by dept by just selecting the min(name)
like below

Select min(emp_name), dept from employee group by dept.

4

If you want a unique list of department names just use the ‘terms’ aggregation on the department field - set the ‘size’ parameter to a larger number or you’ll just get the default of ten results.

5

Thank you @Mark_Harwood for the instant reply. It helped me and I am able to use term aggregation on the department and get unique department names.

When I am fetching the department name, I would also like to fetch the minimum of employee name along with the department name.

Can I do min or max aggregations on text/ keyword fields ?. Can you please help me on this ?

6

That would be another nested terms aggregation inside the department buckets, so -

{
  "aggs": {
	"departments": {
	  "terms": {
		"field": "department"
	  },
	  "aggs":{
		"first_employee":{
		  "terms":{
			"field": "employee_name",
			"order": {
			  "_term": "asc"
			}
		  }
		}
	  }
	}
  }
}
7

Thank you sir.

But nested aggregation for employee inside the departments aggregations will be equal to the below query ?

Select min(emp_name), dept from employee group by dept.

I wanted to know if we can do minimum / maximum aggregation on keyword fields ?

8

Ah. I forgot to add "size":1 in the first_employee aggregation - that should give you the min rather than the default size=10 which would give you the first ten.

9

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