zadd

ZADD

ZADD key [NX|XX] [CH] [INCR] score member [score member ...]

Adds all the specified members with the specified scores to the sorted set stored at key. It is possible to specify multiple score / member pairs. If a specified member is already a member of the sorted set, the score is updated and the element reinserted at the right position to ensure the correct ordering.

If key does not exist, a new sorted set with the specified members as sole members is created, like if the sorted set was empty. If the key exists but does not hold a sorted set, an error is returned.

The score values should be the string representation of a double precision floating point number. +inf and -inf va