#2.5.10 评分的聚合 ZUNIONSTORE destination numkeys key [key ...] [WEIGHTS weight] [AGGREGATE SUM|MIN|MAX]
例如：
127.0.0.1:6379> zrangebyscore votes -inf inf withscores
1) "sina"
2) "1"
3) "google"
4) "5"
5) "baidu"
6) "10"
127.0.0.1:6379> zrangebyscore visits -inf inf withscores
1) "baidu"
2) "1"
3) "google"
4) "5"
5) "sina"
6) "10"
127.0.0.1:6379> zunionstore award 2 visits votes weights 1 2 aggregate sum
(integer) 3
127.0.0.1:6379> zrangebyscore award -inf inf withscores
1) "sina"
2) "12"
3) "google"
4) "15"
5) "baidu"
6) "21"
一个小技巧是如果需要对评分进行倍加，则使用如下的方法：
127.0.0.1:6379>zrangebyscore visits -inf inf withscores
1) "baidu"
2) "1"
3) "google"
4) "5"
5) "sina"
6) "10"
127.0.0.1:6379>zunionstore visits 1 visits weights 2
(integer) 3
127.0.0.1:6379>zrangebyscore visits -inf inf withscores
1) "baidu"
2) "2"
3) "google"
4) "10"
5) "sina"
6) "20"