Available since: 6.2.0
Time complexity: O(L + (N-K)log(N)) worst case where L is the total number of elements in all the sets, N is the size of the first set, and K is the size of the result set.
This command is similar to
ZDIFFSTORE, but instead of storing the resulting
sorted set, it is returned to the client.
Array reply: the result of the difference (optionally with their scores, in case
WITHSCORES option is given).