SDIFF - Upstash Documentation

Use SDIFF to get the members of the first set that are not present in any of the other sets.

Keys that do not exist count as empty sets, so a missing first key yields an empty result. The difference is computed on the fly and nothing is stored; use SDIFFSTORE to keep the result.

It answers questions of the form "who is in A but not in B", such as users who signed up but never converted. The cost grows with the size of the sets involved, so on large sets prefer storing the result and reusing it.

Syntax#

SDIFF <key> [<key> ...]

Arguments#

Argument	Required	Repeatable	Description
`<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	Array of bulk-string members
RESP3	Set of bulk-string members

Note

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

Examples#

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

Redis CLI

SDIFF set1 set2

@upstash/redis

import { Redis } from "@upstash/redis";const redis = Redis.fromEnv();await redis.sadd("set1", "a", "b", "c");await redis.sadd("set2", "c", "d", "e");const diff =  await redis.sdiff("set1", "set2");console.log(diff); // ["a", "b"]

upstash_redis

from upstash_redis import Redisredis = Redis.from_env()result = redis.sdiff("my-key")print(result)

ioredis

import Redis from "ioredis";const redis = new Redis(process.env.REDIS_URL!);const result = await redis.sdiff("my-key");console.log(result);

node-redis

import { createClient } from "redis";const client = await createClient({ url: process.env.REDIS_URL })  .on("error", console.error)  .connect();const result = await client.sDiff("my-key");console.log(result);

redis-py

import osimport redisclient = redis.from_url(os.environ["REDIS_URL"])result = client.sdiff(["my-key"])print(result)

go-redis

package mainimport (    "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.SDiff(context.Background(), "my-key").Result()    if err != nil {        panic(err)    }    fmt.Println(result)}

jedis

import java.net.URI;import redis.clients.jedis.Jedis;try (Jedis jedis = new Jedis(new URI(System.getenv("REDIS_URL")))) {  Object result = jedis.sdiff("my-key");  System.out.println(result);}

redis-rs

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.sdiff(&["my-key"])?;    println!("{result:?}");    Ok(())}