I building a standard free text search on a site that sells cars.
In the search box the user can enter a search word that are passed on to the query where it is used to match both nested and non-nested properties.
I'm using inner_hits to limit the number of variants returned by the query (in this sample variants is not remove from _source)
When matching on a nested property color the inner_hits collection contains the correct variant as expected.
However when matching on a non-nested property title the inner_hits collection is empty. I understand why it's empty.
Can you suggest a better way to structure the query?
Another option would be to always just return at least 1 variant - but how can the be achieved?
Mappings
PUT test
{
"mappings": {
"car": {
"properties": {
"variants": {
"type": "nested"
}
}
}
}
}
Insert data
PUT test/car/1
{
"title": "VW Golf",
"variants": [
{
"color": "red",
"forsale": true
},
{
"color": "blue",
"forsale": false
}
]
}
Query by color
GET test/_search
{
"query": {
"nested": {
"path": "variants",
"query": {
"match": {
"variants.color": "blue"
}
},
"inner_hits": {}
}
}
}
Color query: works as expected!
"hits" : [
{
"_source" : {
"title" : "VW Golf",
"variants" : [
{
"color" : "red",
"forsale" : true
},
{
"color" : "blue",
"forsale" : false
}
]
},
"inner_hits" : {
"variants" : {
"hits" : {
"total" : 1,
"hits" : [
{
"_nested" : {
"field" : "variants",
"offset" : 1
},
"_source" : {
"color" : "blue",
"forsale" : false
}
}
]
}
}
}
}
]
Query by brand
GET test/_search
{
"query": {
"bool": {
"should": [
{
"match": {
"title": "golf"
}
},
{
"nested": {
"path": "variants",
"query": {
"match": {
"variants.color": "golf"
}
},
"inner_hits": {}
}
}
]
}
}
}
Brand query result 
"hits" : [
{
"_source" : {
"title" : "VW Golf",
"variants" : [
{
"color" : "red",
"forsale" : true
},
{
"color" : "blue",
"forsale" : false
}
]
},
"inner_hits" : {
"variants" : {
"hits" : {
"total" : 0,
"hits" : [ ]
}
}
}
}
Cross posted here: https://stackoverflow.com/questions/57166212/nested-inner-hits-in-freetext-search-use-case