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ZDIFF

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ZDIFF numkeys key [key ...] [WITHSCORES]
Group
Sorted set
Complexity
O(L+(N-K)log(N)) worst case, where L is the total number of input members, N the size of the first set and K the size of the result
Arity
-3 (at least 3 words, counting the command name)
Flags
read-only
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ZDIFF returns the members of the first sorted set that do not appear in any of the following ones, ordered by their score in the first set. Scores are not combined: each member keeps its score from the first set.

Inputs can also be plain sets (members score 1), and missing keys count as empty. To store the result instead, use ZDIFFSTORE.

Options

Section titled “Options”
Option Effect
numkeys How many keys follow. Must be at least 1.
WITHSCORES Return each member with its score.

Return value

Section titled “Return value”
Case RESP2 RESP3
Success Array of members Same
With WITHSCORES Flat array: member, score, … (scores as bulk strings) Array of [member, score] pairs, the score a double

Errors:

  • ERR value is not an integer or out of range if numkeys is not an integer, and ERR at least 1 input key is needed for 'zdiff' command if it is below 1.
  • ERR syntax error if fewer keys follow than numkeys says.
  • WRONGTYPE if a key holds something other than a sorted set or a set.

Examples

Section titled “Examples”
127.0.0.1:6379> ZADD all 1 "a" 2 "b" 3 "c"
(integer) 3
127.0.0.1:6379> ZADD done 9 "b"
(integer) 1
127.0.0.1:6379> ZDIFF 2 all done WITHSCORES
1) "a"
2) "1"
3) "c"
4) "3"

Compatibility

Section titled “Compatibility”

Same replies as Redis 7.4 and Valkey 8 for valid input. Extra or unrecognised trailing arguments are ignored, where Redis and Valkey reply ERR syntax error.

See also

Section titled “See also”

ZDIFFSTORE, ZINTER, ZUNION, SDIFF