# SUNIONSTORE

```json metadata
{
  "title": "SUNIONSTORE",
  "description": "Stores the union of multiple sets in a key.",
  "categories": ["docs","develop","stack","oss","rs","rc","oss","kubernetes","clients"],
  "arguments": [{"display_text":"destination","key_spec_index":0,"name":"destination","type":"key"},{"display_text":"key","key_spec_index":1,"multiple":true,"name":"key","type":"key"}],
  "syntax_fmt": "SUNIONSTORE destination key [key ...]",
  "complexity": "O(N) where N is the total number of elements in all given sets.",
  "group": "set",
  "command_flags": ["write","denyoom"],
  "acl_categories": ["@write","@set","@slow"],
  "since": "1.0.0",
  "arity": -3,
  "key_specs": [{"OW":true,"begin_search":{"spec":{"index":1},"type":"index"},"find_keys":{"spec":{"keystep":1,"lastkey":0,"limit":0},"type":"range"},"update":true},{"RO":true,"access":true,"begin_search":{"spec":{"index":2},"type":"index"},"find_keys":{"spec":{"keystep":1,"lastkey":-1,"limit":0},"type":"range"}}],
  "tableOfContents": {"sections":[{"id":"examples","title":"Examples"},{"id":"redis-enterprise-and-redis-cloud-compatibility","title":"Redis Enterprise and Redis Cloud compatibility"},{"id":"return-information","title":"Return information"}]}
}
```













This command is equal to [`SUNION`](https://redis.io/docs/latest/commands/sunion), but instead of returning the resulting set,
it is stored in `destination`.

If `destination` already exists, it is overwritten.

## Examples


SADD key1 "a"
SADD key1 "b"
SADD key1 "c"
SADD key2 "c"
SADD key2 "d"
SADD key2 "e"
SUNIONSTORE key key1 key2
SMEMBERS key


## Redis Enterprise and Redis Cloud compatibility

| Redis<br />Enterprise | Redis<br />Cloud | <span style="min-width: 9em; display: table-cell">Notes</span> |
|:----------------------|:-----------------|:------|
| <span title="Supported">&#x2705; Standard</span><br /><span title="Supported"><nobr>&#x2705; Active-Active</nobr></span> | <span title="Supported">&#x2705; Standard</span><br /><span title="Supported"><nobr>&#x2705; Active-Active</nobr></span> |  |

## Return information

{{< multitabs id="sunionstore-return-info" 
    tab1="RESP2" 
    tab2="RESP3" >}}

[Integer reply](../../develop/reference/protocol-spec#integers): the number of elements in the resulting set.

-tab-sep-

[Integer reply](../../develop/reference/protocol-spec#integers): Number of the elements in the resulting set.