How to perform join between two indexes in ES?

I have two indexes as
Student1.csv and lecture.csv

sample student1.csv

student_id	name	Roll no
1	Amey	1
2	Neha	2
3	Shubham	3
4	Satish	4
5	Ritika	5

sample lecture.csv

lec_no	lec	student_id
1	eng	1
1	eng	1
1	eng	3
1	eng	4
1	eng	5
2	maths	1
2	maths	2
2	maths	3
2	maths	4
2	maths	5
3	sci	1
3	sci	2
3	sci	3
3	sci	4
3	sci	5
4	history	1
4	history	2
4	history	1
4	history	1
4	histoy	3
5	PT	3
5	PT	3
5	PT	3
5	PT	4
5	PT	5

both indexes have a common field student_id
I want to visualize a bar graph on which I want names of top 3 student on X-axis from (student1.csv index) and the count of student_id on Y-axis from( lecture.csv)

I want output in the following way

Elasticsearch does not support joins like that so your best bet is probably to denormalise and store student information on the lecture documents.

So this "JOIN" feature available in elastic (subscription) PlatiĀ­num, EnterĀ­prise mode?

No, Elasticsearch does not support joins at all.

Thanks