# What's the difference between terms and term(with bool should)?
**URL:** https://discuss.elastic.co/t/whats-the-difference-between-terms-and-term-with-bool-should/285186
**Category:** Elasticsearch
**Created:** [September 27, 2021, 3:26am UTC](https://discuss.elastic.co/t/whats-the-difference-between-terms-and-term-with-bool-should/285186 "2021-09-27T03:26:40Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@yeziblo](https://discuss.elastic.co/u/yeziblo)
#### Post date: [September 27, 2021, 3:26am UTC](https://discuss.elastic.co/t/whats-the-difference-between-terms-and-term-with-bool-should/285186/1 "2021-09-27T03:26:40Z")
I've always wondered, for example, about the following statements.
A:
> {
> "bool": {
> "should": [
> {
> "term": {
> "userType": {
> "value": 0
> }
> }
> },
> {
> "term": {
> "userType": {
> "value": 1
> }
> }
> },
> {
> "term": {
> "userType": {
> "value": 2
> }
> }
> },
> {
> "term": {
> "userType": {
> "value": 3
> }
> }
> },
> {
> "term": {
> "userType": {
> "value": 4
> }
> }
> },
> {
> "term": {
> "userType": {
> "value": 5
> }
> }
> }，
> ...
> ]
> }
> }
B:
> {
> "terms": {
> "userType": [
> 0,
> 1,
> 2,
> 3,
> 4,
> 5,
> ...
> ]
> }
> }
Which of them is going to be faster? Is speed also related to the number of terms?
---
### Author:  [@Mark\_Harwood](https://discuss.elastic.co/u/Mark_Harwood)
#### Post date: [September 27, 2021, 8:19am UTC](https://discuss.elastic.co/t/whats-the-difference-between-terms-and-term-with-bool-should/285186/2 "2021-09-27T08:19:45Z")
There's a few differences.
- The simplest to see is the verbosity - `terms` queries just list an array while `term` queries require more JSON.
- `terms` queries do not score matches based on IDF (the rareness) of matched terms - the `term` query does.
- `term` queries can only have up to 1024 values due to Boolean's max clause count
- `terms` queries can have more terms
> By default, Elasticsearch limits the `terms` query to a maximum of 65,536 terms. You can change this limit using the [`index.max_terms_count`](https://www.elastic.co/guide/en/elasticsearch/reference/current/index-modules.html#index-max-terms-count) setting.
> Which of them is going to be faster? Is speed also related to the number of terms?
It depends. They execute differently. `term` queries do more expensive scoring but does so lazily. They may "skip" over docs during execution because other more selective criteria may advance the stream of matching docs considered.
The `terms` queries doesn't do expensive scoring but is more eager and creates the equivalent of a single bitset with a one or zero for every doc by ORing _all_ the potential matching docs up front. Many terms can share the same bitset which is what provides the scalability in term numbers.
---
### Author:  [@yeziblo](https://discuss.elastic.co/u/yeziblo)
#### Post date: [September 27, 2021, 8:56am UTC](https://discuss.elastic.co/t/whats-the-difference-between-terms-and-term-with-bool-should/285186/3 "2021-09-27T08:56:10Z")
It seems like the term query will do scoring, but probably queries for fewer documents, and the terms query does not do scoring, but always queries for all documents that meet the conditions.
> [@Mark\_Harwood](#):
>
> They may "skip" over docs during execution because other more selective criteria may advance the stream of matching docs considered.
I don't quite understand, could you explain it more clearly or give me some relevant documents?
Thank you very much 🙂
---
### Author:  [@Mark\_Harwood](https://discuss.elastic.co/u/Mark_Harwood)
#### Post date: [September 27, 2021, 9:37am UTC](https://discuss.elastic.co/t/whats-the-difference-between-terms-and-term-with-bool-should/285186/4 "2021-09-27T09:37:56Z")
> [@yeziblo](#):
>
> I don't quite understand, could you explain it more clearly
Each term has an ordered "postings list" of documents e.g.
```auto
foo -> 1, 7, 9, 12, 32, 44, ......
bar -> 41, 44, 99
```
If your query has a `must` clause for `bar` and the `foo` is optional then a `bool` query can tell the optional `foo` clause to efficiently skip reading over anything less than 41. The lists of doc ids are encoded in blocks that support skipping over whole chunks of these posting lists.
Also - if `track_total_hits` is false then non-competitive scoring documents can be skipped over. When `bar` is rare and we've already matched enough high-quality docs then the `bool` query can stop asking for more `foo` matches if that is a boring common word because we know these matches aren't going to be interesting enough to make the top results.
---
### Author:  [@yeziblo](https://discuss.elastic.co/u/yeziblo)
#### Post date: [September 28, 2021, 8:50am UTC](https://discuss.elastic.co/t/whats-the-difference-between-terms-and-term-with-bool-should/285186/5 "2021-09-28T08:50:24Z")
Thanks Mark, It's really helpfull!
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [October 26, 2021, 8:50am UTC](https://discuss.elastic.co/t/whats-the-difference-between-terms-and-term-with-bool-should/285186/6 "2021-10-26T08:50:31Z")
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