What's new in Valkey 9.0? Discover new features and improvements. Read the announcement.

ZUNION

Returns the union of multiple sorted sets.

Usage
ZUNION numkeys key ... [WEIGHTS weight ...] [AGGREGATE aggregate] [WITHSCORES withscores]
Complexity
O(N)+O(M*log(M)) with N being the sum of the sizes of the input sorted sets, and M being the number of elements in the resulting sorted set.
Since
6.2.0
ACL Categories
@read, @slow, @sortedset
Command flags
READONLY

This command is similar to ZUNIONSTORE, but instead of storing the resulting sorted set, it is returned to the client.

For a description of the WEIGHTS and AGGREGATE options, see ZUNIONSTORE.

Examples

127.0.0.1:6379> ZADD zset1 1 "one"
(integer) 1
127.0.0.1:6379> ZADD zset1 2 "two"
(integer) 1
127.0.0.1:6379> ZADD zset2 1 "one"
(integer) 1
127.0.0.1:6379> ZADD zset2 2 "two"
(integer) 1
127.0.0.1:6379> ZADD zset2 3 "three"
(integer) 1
127.0.0.1:6379> ZUNION 2 zset1 zset2
1) "one"
2) "three"
3) "two"
127.0.0.1:6379> ZUNION 2 zset1 zset2 WITHSCORES
1) "one"
2) "2"
3) "three"
4) "3"
5) "two"
6) "4"

Replies

RESP2

Array reply: the result of the union with, optionally, their scores when WITHSCORES is used.

RESP3

Array reply: the result of the union with, optionally, their scores when WITHSCORES is used.