opensearch-docs-cn/_search-plugins/sql/sql/index.md

---
layout: default
title: SQL
parent: SQL and PPL
nav_order: 4
has_children: true
has_toc: false
redirect_from:
  - /search-plugins/sql/sql/index/

---

# SQL

## Workbench

The easiest way to get familiar with the SQL plugin is to use **Query Workbench** in OpenSearch Dashboards to test various queries. To learn more, see [Workbench]({{site.url}}{{site.baseurl}}/search-plugins/sql/workbench/).

![OpenSearch Dashboards SQL UI plugin]({{site.url}}{{site.baseurl}}/images/sql.png)

## SQL and OpenSearch terminology

Here’s how core SQL concepts map to OpenSearch:

SQL | OpenSearch
:--- | :---
Table | Index
Row | Document
Column | Field

## REST API

For a complete  REST API reference for the SQL plugin, see [SQL/PPL API]({{site.url}}{{site.baseurl}}/search-plugins/sql/sql-ppl-api). 

To use the SQL plugin with your own applications, send requests to the `_plugins/_sql` endpoint:

```json
POST _plugins/_sql
{
  "query": "SELECT * FROM my-index LIMIT 50"
}
```

You can query multiple indexes by using a comma-separated list:

```json
POST _plugins/_sql
{
  "query": "SELECT * FROM my-index1,myindex2,myindex3 LIMIT 50"
}
```

You can also specify an index pattern with a wildcard expression:

```json
POST _plugins/_sql
{
  "query": "SELECT * FROM my-index* LIMIT 50"
}
```

To run the above query in the command line, use the [curl](https://curl.haxx.se/) command:

```bash
curl -XPOST https://localhost:9200/_plugins/_sql -u 'admin:admin' -k -H 'Content-Type: application/json' -d '{"query": "SELECT * FROM my-index* LIMIT 50"}'
```

You can specify the [response format]({{site.url}}{{site.baseurl}}/search-plugins/sql/response-formats) as JDBC, standard OpenSearch JSON, CSV, or raw. By default, queries return data in JDBC format. The following query sets the format to JSON:

```json
POST _plugins/_sql?format=json
{
  "query": "SELECT * FROM my-index LIMIT 50"
}
```

See the rest of this guide for more information about request parameters, settings, supported operations, and tools.