ZADD _key_ _score_ _member_ (Redis >

Add the specified member having the specifeid score to the sortedset stored at key. If member is already a member of the sorted setthe score is updated, and the element reinserted in the right position toensure sorting. If key does not exist a new sorted set with the specified_member_ as sole member is crated. If the key exists but does not hold asorted set value an error is returned.

The score value can be the string representation of a double precision floatingpoint number.

For an introduction to sorted sets check the Introduction to Redis data types page.

Return value

1 if the new element was added
0 if the element was already a member of the sorted set and the score was updated