SDIFF key [key …]
Time complexity: O(N) where N is the total number of elements in all given sets.
Returns the members of the set resulting from the difference between the first set and all the successive sets.
For example:
: list with members of the resulting set.
*Examples
redis> SADD key1 "a"
- (integer) 1
redis> SADD key1 "b"
redis> SADD key2 "c"
redis> SADD key2 "d"
- (integer) 1
redis> SADD key2 "e"
redis>
- 2) "b"