You can perform a Boolean query with the `bool` query type. A Boolean query compounds query clauses so you can combine multiple search queries with Boolean logic. To narrow or broaden your search results, use the `bool` query clause rules.
`must` | Logical `and` operator. The results must match the queries in this clause. If you have multiple queries, all of them must match.
`must_not` | Logical `not` operator. All matches are excluded from the results.
`should` | Logical `or` operator. The results must match at least one of the queries, but, optionally, they can match more than one query. Each matching `should` clause increases the relevancy score. You can set the minimum number of queries that must match using the `minimum_number_should_match` parameter.
`minimum_number_should_match` | Optional parameter for use with a `should` query clause. Specifies the minimum number of queries that the document must match for it to be returned in the results. The default value is 1.
`filter` | Logical `and` operator that is applied first to reduce your dataset before applying the queries. A query within a filter clause is a yes or no option. If a document matches the query, it is returned in the results; otherwise, it is not. The results of a filter query are generally cached to allow for a faster return. Use the filter query to filter the results based on exact matches, ranges, dates, numbers, and so on.
For example, assume you have the complete works of Shakespeare indexed in an OpenSearch cluster. You want to construct a single query that meets the following requirements:
1. The `text_entry` field must contain the word `love` and should contain either `life` or `grace`.
2. The `speaker` field must not contain `ROMEO`.
3. Filter these results to the play `Romeo and Juliet` without affecting the relevancy score.
Use the following query:
```json
GET shakespeare/_search
{
"query": {
"bool": {
"must": [
{
"match": {
"text_entry": "love"
}
}
],
"should": [
{
"match": {
"text_entry": "life"
}
},
{
"match": {
"text_entry": "grace"
}
}
],
"minimum_should_match": 1,
"must_not": [
{
"match": {
"speaker": "ROMEO"
}
}
],
"filter": {
"term": {
"play_name": "Romeo and Juliet"
}
}
}
}
}
```
#### Sample output
```json
{
"took": 12,
"timed_out": false,
"_shards": {
"total": 4,
"successful": 4,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 11.356054,
"hits": [
{
"_index": "shakespeare",
"_id": "88020",
"_score": 11.356054,
"_source": {
"type": "line",
"line_id": 88021,
"play_name": "Romeo and Juliet",
"speech_number": 19,
"line_number": "4.5.61",
"speaker": "PARIS",
"text_entry": "O love! O life! not life, but love in death!"
}
}
]
}
}
```
If you want to identify which of these clauses actually caused the matching results, name each query with the `_name` parameter.
To add the `_name` parameter, change the field name in the `match` query to an object:
```json
GET shakespeare/_search
{
"query": {
"bool": {
"must": [
{
"match": {
"text_entry": {
"query": "love",
"_name": "love-must"
}
}
}
],
"should": [
{
"match": {
"text_entry": {
"query": "life",
"_name": "life-should"
}
}
},
{
"match": {
"text_entry": {
"query": "grace",
"_name": "grace-should"
}
}
}
],
"minimum_should_match": 1,
"must_not": [
{
"match": {
"speaker": {
"query": "ROMEO",
"_name": "ROMEO-must-not"
}
}
}
],
"filter": {
"term": {
"play_name": "Romeo and Juliet"
}
}
}
}
}
```
OpenSearch returns a `matched_queries` array that lists the queries that matched these results:
```json
"matched_queries": [
"love-must",
"life-should"
]
```
If you remove the queries not in this list, you will still see the exact same result.
By examining which `should` clause matched, you can better understand the relevancy score of the results.
