Redis zcount 命令

ZCOUNT key min max

Returns the number of elements in the sorted set at key with a score between
min and max.

The min and max arguments have the same semantic as described for ZRANGEBYSCORE.

Note: the command has a complexity of just O(log(N)) because it uses elements ranks (see ZRANK) to get an idea of the range. Because of this there is no need to do a work proportional to the size of the range.

*返回值

Integer reply: the number of elements in the specified score range.

*实例

redis>  ZADD myzset 1 “one”

(integer) 1

redis>  ZADD myzset 2 “two”

(integer) 1

redis>  ZADD myzset 3 “three”

(integer) 1

redis>  ZCOUNT myzset -inf +inf

(integer) 3

redis>  ZCOUNT myzset (1 3

(integer) 2

redis>