How do I construct this elasticsearch query object? - elasticsearch

Question

My documents are indexed like this:
{
title: "stuff here",
description: "stuff here",
keywords: "stuff here",
score1: "number here",
score2: "number here"
}
I want to perform a query that:
Uses the title, description, and keywords fields for matching the text terms.
It doesn't have to be complete match. Eg. If someone searches "I have a big nose", and "nose" is in one of the document titles but "big" is not, then this document should still be returned.
Edit: I tried this query and it works. Can someone confirm if this is the right way to do it? Thanks.
{
query:{
'multi_match':{
'query': q,
'fields': ['title^2','description', 'keywords'],
}
}
}

Answer 1

Your way is definitely the way to go!
The multi_match query is usually the one that you want to expose to the end users, while the query_string is similar, but also more powerful and dangerous since it exposes the lucene query syntax. Rule of thumb: don't use query string if you don't need it.
Also, searching on multiple fields is easy just providing the list of fields you want to search on, as you did, without the need for a bool query.

Answer 2

Below is the code that will create the query you can use. I wrote it in c# but it will work in other languages in the same way.
What you need to do is to create a BooleanQuery and set that at least 1 of its condition has to match. Then add a condition for every document field you want to be checked with Occur.SHOULD enum value:
BooleanQuery searchQuery = new BooleanQuery();
searchQuery.SetMinimumNumberShouldMatch(1);
QueryParser parser = new QueryParser(Lucene.Net.Util.Version.LUCENE_29, "title", new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_29));
Query titleQuery = parser.Parse("I have a big nose");
searchQuery.Add(titleQuery, BooleanClause.Occur.SHOULD);
parser = new QueryParser(Lucene.Net.Util.Version.LUCENE_29, "description", new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_29));
Query descriptionQuery = parser.Parse("I have a big nose");
searchQuery.Add(titleQuery, BooleanClause.Occur.SHOULD);
parser = new QueryParser(Lucene.Net.Util.Version.LUCENE_29, "keywords", new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_29));
Query keywordsQuery = parser.Parse("I have a big nose");
searchQuery.Add(titleQuery, BooleanClause.Occur.SHOULD);
Query queryThatShouldBeExecuted.Add(searchQuery, BooleanClause.Occur.MUST);
Here is the link to an example in java http://www.javadocexamples.com/java_source/org/apache/lucene/search/TestBooleanMinShouldMatch.java.html

Answer 3

The according JSON object to perform a HTTP Post request would be this:
{
"bool": {
"should": [
{
"query_string": {
"query": "I have a big nose",
"default_field": "title"
}
},
{
"query_string": {
"query": "I have a big nose",
"default_field": "description"
}
},
{
"query_string": {
"query": "I have a big nose",
"default_field": "keywords"
}
}
],
"minimum_number_should_match": 1,
"boost": 1
}
}