Search for documents matching all terms in a nested array Elasticsearch - elasticsearch

Question

I am learning to use Elasticsearch as a basic recommender engine.
My elasticsearch document contains records with nested entities as follows
PUT recs/user/1
{
"name" : "Brad Pitt",
"movies_liked": [
{
"name": "Forrest Gump",
"score": 1
},
{
"name": "Terminator",
"score": 4
},
{
"name": "Rambo",
"score": 4
},
{
"name": "Rocky",
"score": 4
},
{
"name": "Good Will Hunting",
"score": 2
}
]
}
PUT recs/user/2
{
"name" : "Tom Cruise",
"movies_liked": [
{
"name": "Forrest Gump",
"score": 2
},
{
"name": "Terminator",
"score": 1
},
{
"name": "Rocky IV",
"score": 1
},
{
"name": "Rocky",
"score": 1
},
{
"name": "Rocky II",
"score": 1
},
{
"name": "Predator",
"score": 4
}
]
}
I would like to search for users who specifically like "Forrest Gump","Terminator" and "Rambo".
I have used a nested query which currently looks like this
POST recs/user/_search
{
"query": {
"nested": {
"path": "movies_liked",
"query": {
"terms": {
"movies_liked.name": ["Forrest Gump","Terminator","Rambo"]
}
}
}
}
}
However when I execute this search, I expected to see only the first record which has all the required terms, but in the results I am getting both the records. In the second record the user clearly does not have "Rambo" in his liked list. I understand that this query is doing an "OR" operation with the given terms, How do I tweak this query to do an "AND" operation so that only the records having all the terms get matched?

Answer 1

How do I tweak this query to do an "AND" operation so that only the records having all the terms get matched?
By using a bool query:
POST recs/user/_search
{
"query": {
"bool": {
"must": [
{
"nested": {
"path": "movies_liked",
"query": {
"bool": {
"must": [
{
"terms": {
"movies_liked.name": [
"Forrest Gump"
]
}
}
]
}
}
}
},
{
"nested": {
"path": "movies_liked",
"query": {
"bool": {
"must": [
{
"terms": {
"movies_liked.name": [
"Terminator"
]
}
}
]
}
}
}
},
{
"nested": {
"path": "movies_liked",
"query": {
"bool": {
"must": [
{
"terms": {
"movies_liked.name": [
"Rambo"
]
}
}
]
}
}
}
}
]
}
}
}
Note that bool wraps around several nested queries, not the other way around. It is important because the scope of a nested query is the nested document, because it basically a hidden separate object.
Hope that helps!