> ## Documentation Index
> Fetch the complete documentation index at: https://upstash.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# SUNIONSTORE

> Store set union.

Use `SUNIONSTORE` to compute the union of sets and store it in another key.

The destination is overwritten if it exists and deleted when the union is empty, and the reply is the number of members stored. Materializing the union is the usual way to build a combined audience once and then intersect or difference it with other sets, instead of recomputing it on every query.

## Syntax

```redis theme={"system"}
SUNIONSTORE <destination> <key> [<key> ...]
```

## Arguments

| Argument        | Required | Repeatable | Description                        |
| --------------- | -------- | ---------- | ---------------------------------- |
| `<destination>` | Yes      | No         | Redis key used as destination.     |
| `<key>`         | Yes      | Yes        | Redis key targeted by the command. |

## Response

The reply reports the result of the operation. Error replies have the same shape in RESP2 and RESP3 and are surfaced as exceptions by the SDKs below.

| Protocol | Reply   |
| -------- | ------- |
| RESP2    | Integer |
| RESP3    | Integer |

<Note>
  Client libraries often decode bulk strings, maps, sets, and numeric strings into language-native values. The table describes the Redis wire reply.
</Note>

## Examples

TCP examples use the TLS `REDIS_URL` from the Upstash console. REST examples use `UPSTASH_REDIS_REST_URL` and `UPSTASH_REDIS_REST_TOKEN`.

<AccordionGroup>
  <Accordion title="Redis CLI" icon="terminal">
    ```bash theme={"system"}
    SUNIONSTORE destination set1 set2
    ```
  </Accordion>

  <Accordion title="@upstash/redis" icon="node-js" iconType="brands">
    ```ts theme={"system"}
    import { Redis } from "@upstash/redis";

    const redis = Redis.fromEnv();

    await redis.sadd("set1", "a", "b", "c");
    await redis.sadd("set2", "c", "d", "e");
    await redis.sunionstore("destination", "set1", "set2");
    ```
  </Accordion>

  <Accordion title="upstash_redis" icon="python" iconType="brands">
    ```python theme={"system"}
    from upstash_redis import Redis

    redis = Redis.from_env()
    result = redis.sunionstore("destination-key", "my-key")
    print(result)
    ```
  </Accordion>

  <Accordion title="ioredis" icon="node-js" iconType="brands">
    ```ts theme={"system"}
    import Redis from "ioredis";

    const redis = new Redis(process.env.REDIS_URL!);
    const result = await redis.sunionstore("destination-key", "my-key");
    console.log(result);
    ```
  </Accordion>

  <Accordion title="node-redis" icon="node-js" iconType="brands">
    ```ts theme={"system"}
    import { createClient } from "redis";

    const client = await createClient({ url: process.env.REDIS_URL })
      .on("error", console.error)
      .connect();
    const result = await client.sUnionStore("destination-key", "my-key");
    console.log(result);
    ```
  </Accordion>

  <Accordion title="redis-py" icon="python" iconType="brands">
    ```python theme={"system"}
    import os
    import redis

    client = redis.from_url(os.environ["REDIS_URL"])
    result = client.sunionstore("destination-key", ["my-key"])
    print(result)
    ```
  </Accordion>

  <Accordion title="go-redis" icon="golang" iconType="brands">
    ```go theme={"system"}
    package main

    import (
        "context"
        "fmt"
        "os"

        "github.com/redis/go-redis/v9"
    )

    func main() {
        opts, err := redis.ParseURL(os.Getenv("REDIS_URL"))
        if err != nil {
            panic(err)
        }
        client := redis.NewClient(opts)
        result, err := client.SUnionStore(context.Background(), "destination-key", "my-key").Result()
        if err != nil {
            panic(err)
        }
        fmt.Println(result)
    }
    ```
  </Accordion>

  <Accordion title="jedis" icon="java" iconType="brands">
    ```java theme={"system"}
    import java.net.URI;

    import redis.clients.jedis.Jedis;

    try (Jedis jedis = new Jedis(new URI(System.getenv("REDIS_URL")))) {
      Object result = jedis.sunionstore("destination-key", "my-key");
      System.out.println(result);
    }
    ```
  </Accordion>

  <Accordion title="redis-rs" icon="rust" iconType="brands">
    ```rust theme={"system"}
    use redis::TypedCommands;

    fn main() -> redis::RedisResult<()> {
        let url = std::env::var("REDIS_URL").expect("REDIS_URL is not set");
        let client = redis::Client::open(url)?;
        let mut connection = client.get_connection()?;

        let result = connection.sunionstore("destination-key", &["my-key"])?;
        println!("{result:?}");
        Ok(())
    }
    ```
  </Accordion>
</AccordionGroup>


## Related topics

- [SUNIONSTORE](/docs/redis/sdks/py/commands/set/sunionstore.md)
- [SUNION](/docs/redis/commands/set/sunion.md)
- [Overview](/docs/redis/sdks/py/commands/overview.md)