Add the specified members to the set stored at key. Specified members that are already a member of this set are ignored. If key does not exist, a new set is created before adding the specified members.

An error is returned when the value stored at key is not a set.

@return

@integer-reply: the number of elements that were added to the set, not including all the elements already present into the set.

@history

• >= 2.4: Accepts multiple member arguments. Redis versions before 2.4 are only able to add a single member per call.

@examples

SADD myset "Hello"
SADD myset "World"
SADD myset "World"
SMEMBERS myset