In Elasticsearch, how do I search string on multiple fields from multi-level nested objects - elasticsearch

Question

In Elasticsearch 6, I have data with nested objects like this:
{
"brands" :
[
{
"brand_name" : "xyz",
"products" :
[
{
"title" : "test",
"mrp" : 100,
"sp" : 90,
"status" : 1
},
{
"title" : "test1",
"mrp" : 50,
"sp" : 45,
"status" : 1
}
]
},
{
"brand_name" : "aaa",
"products" :
[
{
"title" : "xyz",
"mrp" : 100,
"sp" : 90,
"status" : 1
},
{
"title" : "abc",
"mrp" : 50,
"sp" : 45,
"status" : 1
}
]
}
]
}
I want to search from either from the field brand_name or from the field title. And I want return all results in same inner_hits.
For example : If I input the search string as "xyz" it should return both brands object with correspondent product object.
If I input the search string as "test" it should return only first brand array with only first product object.
How can I achieve this. Any ideas?
I have tried with the nested path query like this:
{
"query": {
"bool": {
"must": [
{
"nested": {
"path": "brands",
"query": {
"bool": {
"should": [
{
"term": {
"brands.brand_name": "xyz"
}
},
{
"term": {
"brands.brand_name.keyword": "aaa"
}
},
{
"nested": {
"path": "brands.products",
"query": {
"bool": {
"should": [
{
"match": {
"brands.products.title": "xyz"
}
}
]
}
},
"inner_hits": {}
}
}
]
}
},
"inner_hits": {}
}
}
]
}
}
}
But this query returning with multiple inner_hits response with multiple array objects for each brands and for each products.
I want the response like all brand names which is matching with the string should list under one array and all the products should list under another array under same inner_hits.

Answer 1

Since you want the inner hits to be different based on where the match has happened i.e. brands.brand_name or brands.products.title, you can have two queries one for brand name and other for product title as independent nested queries. These queries then should be inside should clause of a bool query. Each of the nested query should have its own inner_hits as below:
{
"query": {
"bool": {
"should": [
{
"nested": {
"path": "brands",
"inner_hits": {},
"query": {
"term": {
"brands.brand_name.keyword": "test"
}
}
}
},
{
"nested": {
"path": "brands.products",
"inner_hits": {},
"query": {
"term": {
"brands.products.title": "test"
}
}
}
}
]
}
},
"_source": false
}