返回给定的多个集合的并集中的所有成员.

例如:

key1 = {a,b,c,d}
key2 = {c}
key3 = {a,c,e}
SUNION key1 key2 key3 = {a,b,c,d,e}

不存在的key可以认为是空的集合.

##返回值

array-reply:并集的成员列表

##举例

redis> SADD key1 "a"
(integer) 1
redis> SADD key1 "b"
(integer) 1
redis> SADD key1 "c"
(integer) 1
redis> SADD key2 "c"
(integer) 1
redis> SADD key2 "d"
(integer) 1
redis> SADD key2 "e"
(integer) 1
redis> SUNION key1 key2
1) "a"
2) "b"
3) "c"
4) "d"
5) "e"
redis>