Elasticsearch match one array with another array - elasticsearch

Question

Let's say I have two indexes kids and outings_for_kids with the following data
kids
[
{
"name": "little kid 1",
"i_like":["drawing","teddybears"]
},
]
outings for kids
[
{
"name": "Teddybear drawing fights with apples!",
"for_kids_that_like":["apples","teddybears","drawing", "play outside games"]
},
{
"name": "drawing and teddies!",
"for_kids_that_like":["teddybears","drawing"]
}
]
I want to find an outing that likes the same things little kid 1 likes and a lower score if it has more.
Little kid 1 should not match 100% with the first outing. It has what little kid 1 wants, but but it has more e.g. apples, it should match 50%.
It should match 100% with the second outing.

Answer 1

This will be a 2 step process:
Get i_like value from fields index
Use i_like from step 1 to query outings index
Use terms query to match each value
Use script to compare array size with number of values
Use constant score to give same score based on index count
Query
GET outings/_search
{
"query": {
"bool": {
"should": [
{
"constant_score": {
"filter": {
"bool": {
"must": [
{
"term": {
"for_kids_that_like": {
"value": "teddybears"
}
}
},
{
"term": {
"for_kids_that_like": {
"value": "drawing"
}
}
},
{
"script": {
"script": "doc['for_kids_that_like.keyword'].size()==2" --> replace 2 with size of elements searched
}
}
]
}
},
"boost": 100
}
},
{
"constant_score": {
"filter": {
"bool": {
"must": [
{
"term": {
"for_kids_that_like": {
"value": "teddybears"
}
}
},
{
"term": {
"for_kids_that_like": {
"value": "drawing"
}
}
},
{
"script": {
"script": "doc['for_kids_that_like.keyword'].size()>2"
}
}
]
}
},
"boost": 50
}
}
]
}
}
}
Result:
"hits" : [
{
"_index" : "outings",
"_type" : "_doc",
"_id" : "IH7tVHEBbLcSRUWr6wPj",
"_score" : 100.0,
"_source" : {
"name" : "Teddybear drawing fights with apples!",
"for_kids_that_like" : [
"teddybears",
"drawing"
]
}
},
{
"_index" : "outings",
"_type" : "_doc",
"_id" : "IX7zVHEBbLcSRUWrhgM9",
"_score" : 50.0,
"_source" : {
"name" : "Teddybear drawing fights with apples!",
"for_kids_that_like" : [
"teddybears",
"drawing",
"apples"
]
}
}
]
If you just want to show exact match documents on top followed by partial matches then you don't need constant score(must query with term search will work). By default exact matches are given higher score