Sorted Sets

Redis Sorted Sets

A sorted set is like a set (unique members) but each member has an associated floating-point score. Members are always kept in score order. Sorted sets are perfect for leaderboards, rankings, and priority queues.

ZADD — Add Members with Scores

ZADD leaderboard 100 "Alice" 85 "Bob" 92 "Charlie"

Returns the number of new members added (not updated).

ZRANGE — Get Members in Score Order (Ascending)

ZRANGE leaderboard 0 -1
ZRANGE leaderboard 0 -1 WITHSCORES

Output:

1) "Bob"
2) "Charlie"
3) "Alice"
---
1) "Bob"
2) "85"
3) "Charlie"
4) "92"
5) "Alice"
6) "100"

ZREVRANGE — Get Members in Reverse Order (Descending)

ZREVRANGE leaderboard 0 2 WITHSCORES

Returns top 3, highest score first.

ZRANK and ZREVRANK — Get Rank

ZRANK leaderboard "Alice"       -- 2 (0-indexed, ascending)
ZREVRANK leaderboard "Alice"    -- 0 (0-indexed, descending = rank 1)

ZSCORE — Get Score

ZSCORE leaderboard "Alice"    -- "100"

ZINCRBY — Change Score

ZINCRBY leaderboard 15 "Bob"
ZSCORE leaderboard "Bob"    -- "100"

ZCARD — Number of Members

ZCARD leaderboard    -- 3

ZRANGEBYSCORE — Range by Score

ZRANGEBYSCORE leaderboard 90 100    -- members scoring 90-100
ZRANGEBYSCORE leaderboard -inf +inf -- all members
ZRANGEBYSCORE leaderboard (85 100   -- exclusive lower bound (>85)

Real-World Uses

Gaming leaderboard:

ZADD game:scores 1200 "Charlie" 1000 "Alice" 750 "Bob"
ZREVRANGE game:scores 0 2 WITHSCORES    -- top 3

Priority queue:

ZADD tasks 1 "critical-bug" 5 "feature" 3 "refactor"
ZPOPMIN tasks    -- get highest priority (lowest score)

Your Task

Build a leaderboard scores with: "Alice" at 100, "Bob" at 75, "Charlie" at 92, "Dave" at 88. Then use ZREVRANGE to get all members with scores, highest first.