How do I query/filter by index of an array in elasticsearch?
I have a document like this:-
PUT /edi832/record/1
{
"LIN": [ "UP", "123456789" ]
}
I want to search if LIN[0] is "UP" and LIN[1] exists.
Thanks.
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1 Answer
This might look like a hack , but then it will work for sure. First we apply token count type along with multi field to capture the the number of tokens as a field. So the mapping will look like this -
{
"record" : {
"properties" : {
"LIN" : {
"type" : "string",
"fields" : {
"word_count": {
"type" : "token_count",
"store" : "yes",
"analyzer" : "standard"
}
}
}
}
}
}
So to check if the second field exists , its as easy as checking if this field value is more than or equal to 2. Next we can use the token filter to check if the token "up" exists in position 0. We can use the scripted filter to check this. Hence a query like below should work -
{
"query": {
"filtered": {
"query": {
"range": {
"LIN.word_count": {
"gte": 2
}
}
},
"filter": {
"script": {
"script": "for(pos : _index['LIN'].get('up',_POSITIONS)){ if(pos.position == 0) { return true}};return false;"
}
}
}
}
}
Advanced scripting - http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/modules-advanced-scripting.html
Script filters - http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-script-filter.html
3 Comments
Andrei Stefan
Looks good. But if the author of the post has no problem with changing the mapping of the index, I'd say that approach plus the
bool query is more efficient.
Vineeth Mohan
How can we make sure the token 'up' comes first , in the approach you have recommended ?
Thanigs
Thanks @Vineeth Mohan. I have accepted this answer. It provides enough pointers to build up on this.