ZUNION numkeys key [key ...] [WEIGHTS weight [weight ...]] [AGGREGATE SUM | MIN | MAX] [WITHSCORES]
Available since: 6.2.0
Time 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.
ACL categories:
@read
@sortedset
@slow
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.
Return
Array reply: the result of union (optionally with their scores, in case
the WITHSCORES option is given).