opensearch-docs-cn/docs/sql/endpoints.md

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2021-05-05 13:09:47 -04:00
---
layout: default
title: Endpoint
parent: SQL
nav_order: 13
---
# Endpoint
To send query request to SQL plugin, you can either use a request
parameter in HTTP GET or request body by HTTP POST request. POST request
is recommended because it doesn't have length limitation and allows for
other parameters passed to plugin for other functionality such as
prepared statement. And also the explain endpoint is used very often for
query translation and troubleshooting.
## GET
### Description
You can send HTTP GET request with your query embedded in URL parameter.
### Example
SQL query:
```console
>> curl -H 'Content-Type: application/json' -X GET localhost:9200/_opensearch/_sql?sql=SELECT * FROM accounts
```
## POST
### Description
You can also send HTTP POST request with your query in request body.
### Example
SQL query:
```console
>> curl -H 'Content-Type: application/json' -X POST localhost:9200/_opensearch/_sql -d '{
"query" : "SELECT * FROM accounts"
}'
```
## Explain
### Description
To translate your query, send it to explain endpoint. The explain output
is OpenSearch domain specific language (DSL) in JSON format. You can
just copy and paste it to your console to run it against OpenSearch
directly.
### Example
Explain query:
```console
>> curl -H 'Content-Type: application/json' -X POST localhost:9200/_opensearch/_sql/_explain -d '{
"query" : "SELECT firstname, lastname FROM accounts WHERE age > 20"
}'
```
Explain:
```json
{
"from": 0,
"size": 200,
"query": {
"bool": {
"filter": [{
"bool": {
"must": [{
"range": {
"age": {
"from": 20,
"to": null,
"include_lower": false,
"include_upper": true,
"boost": 1.0
}
}
}],
"adjust_pure_negative": true,
"boost": 1.0
}
}],
"adjust_pure_negative": true,
"boost": 1.0
}
},
"_source": {
"includes": [
"firstname",
"lastname"
],
"excludes": []
}
}
```
## Cursor
### Description
To get back a paginated response, use the `fetch_size` parameter. The value of `fetch_size` should be greater than 0. The default value is 1,000. A value of 0 will fallback to a non-paginated response.
The `fetch_size` parameter is only supported for the JDBC response format.
{: .note }
### Example
SQL query:
```console
>> curl -H 'Content-Type: application/json' -X POST localhost:9200/_opensearch/_sql -d '{
"fetch_size" : 5,
"query" : "SELECT firstname, lastname FROM accounts WHERE age > 20 ORDER BY state ASC"
}'
```
Result set:
```json
{
"schema": [
{
"name": "firstname",
"type": "text"
},
{
"name": "lastname",
"type": "text"
}
],
"cursor": "d:eyJhIjp7fSwicyI6IkRYRjFaWEo1UVc1a1JtVjBZMmdCQUFBQUFBQUFBQU1XZWpkdFRFRkZUMlpTZEZkeFdsWnJkRlZoYnpaeVVRPT0iLCJjIjpbeyJuYW1lIjoiZmlyc3RuYW1lIiwidHlwZSI6InRleHQifSx7Im5hbWUiOiJsYXN0bmFtZSIsInR5cGUiOiJ0ZXh0In1dLCJmIjo1LCJpIjoiYWNjb3VudHMiLCJsIjo5NTF9",
"total": 956,
"datarows": [
[
"Cherry",
"Carey"
],
[
"Lindsey",
"Hawkins"
],
[
"Sargent",
"Powers"
],
[
"Campos",
"Olsen"
],
[
"Savannah",
"Kirby"
]
],
"size": 5,
"status": 200
}
```
To fetch subsequent pages, use the `cursor` from last response:
```console
>> curl -H 'Content-Type: application/json' -X POST localhost:9200/_opensearch/_sql -d '{
"cursor": "d:eyJhIjp7fSwicyI6IkRYRjFaWEo1UVc1a1JtVjBZMmdCQUFBQUFBQUFBQU1XZWpkdFRFRkZUMlpTZEZkeFdsWnJkRlZoYnpaeVVRPT0iLCJjIjpbeyJuYW1lIjoiZmlyc3RuYW1lIiwidHlwZSI6InRleHQifSx7Im5hbWUiOiJsYXN0bmFtZSIsInR5cGUiOiJ0ZXh0In1dLCJmIjo1LCJpIjoiYWNjb3VudHMiLCJsIjo5NTF9"
}'
```
The result only has the `fetch_size` number of `datarows` and `cursor`.
The last page has only `datarows` and no `cursor`.
The `datarows` can have more than the `fetch_size` number of records in case the nested fields are flattened.
```json
{
"cursor": "d:eyJhIjp7fSwicyI6IkRYRjFaWEo1UVc1a1JtVjBZMmdCQUFBQUFBQUFBQU1XZWpkdFRFRkZUMlpTZEZkeFdsWnJkRlZoYnpaeVVRPT0iLCJjIjpbeyJuYW1lIjoiZmlyc3RuYW1lIiwidHlwZSI6InRleHQifSx7Im5hbWUiOiJsYXN0bmFtZSIsInR5cGUiOiJ0ZXh0In1dLCJmIjo1LCJpIjoiYWNjb3VudHMabcde12345",
"datarows": [
[
"Abbas",
"Hussain"
],
[
"Chen",
"Dai"
],
[
"Anirudha",
"Jadhav"
],
[
"Peng",
"Huo"
],
[
"John",
"Doe"
]
]
}
```
The `cursor` context is automatically cleared on the last page.
To explicitly clear cursor context, use the `_opensearch/_sql/close endpoint` operation.
```console
>> curl -H 'Content-Type: application/json' -X POST localhost:9200/_opensearch/_sql/close -d '{
"cursor": "d:eyJhIjp7fSwicyI6IkRYRjFaWEo1UVc1a1JtVjBZMmdCQUFBQUFBQUFBQU1XZWpkdFRFRkZUMlpTZEZkeFdsWnJkRlZoYnpaeVVRPT0iLCJjIjpbeyJuYW1lIjoiZmlyc3RuYW1lIiwidHlwZSI6InRleHQifSx7Im5hbWUiOiJsYXN0bmFtZSIsInR5cGUiOiJ0ZXh0In1dLCJmIjo1LCJpIjoiYWNjb3VudHMiLCJsIjo5NTF9"
}'
```
#### Sample response
```json
{"succeeded":true}
```