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ZUNIONSTORE

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ZUNIONSTORE destination numkeys key [key ...] [WEIGHTS weight [weight ...]] [AGGREGATE SUM | MIN | MAX]
Group
Sorted set
Complexity
O(N)+O(M*log(M)) where N is the total size of the input sets and M is the size of the result
Arity
-4 (at least 4 words, counting the command name)
Flags
write
Keys
first 1, last 1, step 1
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ZUNIONSTORE computes the same union as ZUNION and stores it as a sorted set at destination, replacing whatever was there. If the result is empty, destination is deleted. The inputs are read and the result written as one atomic step, and destination can also be one of the inputs.

Inputs can be sorted sets or plain sets (members score 1); missing keys count as empty.

Options

Section titled “Options”
Option Effect
numkeys How many keys follow. Must be at least 1.
WEIGHTS weight ... One multiplier per input key, applied before combining. Default 1 each.
AGGREGATE SUM | MIN | MAX How scores of a shared member combine. Default SUM.

WITHSCORES is not accepted.

Return value

Section titled “Return value”
Case RESP2 RESP3
Success Integer: the number of members in the stored sorted set Same

Errors are those of ZUNION, with the command named zunionstore in the numkeys error; WITHSCORES gives ERR syntax error.

Examples

Section titled “Examples”
127.0.0.1:6379> ZADD q1 10 "alice" 5 "bob"
(integer) 2
127.0.0.1:6379> ZADD q2 3 "bob" 7 "carol"
(integer) 2
127.0.0.1:6379> ZUNIONSTORE total 2 q1 q2
(integer) 3
127.0.0.1:6379> ZRANGE total 0 -1 WITHSCORES
1) "carol"
2) "7"
3) "bob"
4) "8"
5) "alice"
6) "10"

Compatibility

Section titled “Compatibility”

Same as Redis 7.4 and Valkey 8.

See also

Section titled “See also”

ZUNION, ZINTERSTORE, ZDIFFSTORE, SUNIONSTORE