SUNIONSTORE

Available since 1.0.0.

Time complexity: O(N) where N is the total number of elements in all given sets.

This command is equal to SUNION, but instead of returning the resulting set, it is stored in destination.

If destination already exists, it is overwritten.

*Return value

Integer reply: the number of elements in the resulting set.

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> SUNIONSTORE key key1 key2

(integer) 5

redis> SMEMBERS key

1) "c"
2) "e"
3) "b"
4) "a"
5) "d"