Multiple indices with different fields

Elastic Stack Elasticsearch
1

Hi All,
I know ES is not RDBMS and not possible to join but wanted to ask experts opinion here.
I want to pull data from two different indices (idx1, idx2) with different fields as below

query: match: idx1.fld1=idx2.fld2 AND idx1.fld3 = idx2.fldx4

Any suggestions here, plz.

Thank you

2

I think you answered yourself.

Joins are not possible unless you use the parent child feature.
It's better to do the join at index time.