ZINTERCARD(3valkey)

📦
version 9.0.6 · 2 versions
, in fedora 44

✨ ZINTERCARD ✨

valkey manual page, bestie — and yes we're doing the whole thing, so grab a snack 🍓

NAME 💅

zintercard — returns the number of members of the intersect of multiple sorted sets. that's it, that's the girl. she counts. she does not return. iconic behavior honestly 👑

SYNOPSIS 🌸

ZINTERCARD numkeys key [key...] [LIMIT limit]

DESCRIPTION 🦋

okay so. this command is basically ZINTER's sibling, but she's the low-key one — instead of handing you the whole result set, she just gives you the cardinality of the result. just the number. no extra drama. 💅

keys that don't exist? consider them empty sets, bestie. and if even one of your keys is an empty set, the resulting set is empty too — because set intersection with an empty set always gives you an empty set. math said no. 😭

by default, the command calculates the cardinality of the intersection of all the sets you gave it. but when you pass the optional LIMIT argument — which defaults to 0 and means unlimited — something cute happens: if the intersection cardinality reaches limit partway through the computation, the algorithm just exits and yields limit as the cardinality. and that implementation? it ensures a significant speedup for queries where the limit is lower than the actual intersection cardinality. queen of not doing extra work, we love to see it 🔥

REPLY 💖

valkey-protocol(7) Integer reply: the number of members in the resulting intersection.

COMPLEXITY 🧚

O(N*K) worst case, with N being the smallest input sorted set and K being the number of input sorted sets.

ACL CATEGORIES 🎀</bad>

@read @slow @sortedset

HISTORY ⭐

  • Available since: 7.0.0

EXAMPLES 🌈

okay watch this, fr fr:

127.0.0.1:6379> ZADD zset1 1 "one"
(integer) 1
127.0.0.1:6379> ZADD zset1 2 "two"
(integer) 1
127.0.0.1:6379> ZADD zset2 1 "one"
(integer) 1
127.0.0.1:6379> ZADD zset2 2 "two"
(integer) 1
127.0.0.1:6379> ZADD zset2 3 "three"
(integer) 1
127.0.0.1:6379> ZINTER 2 zset1 zset2
1) "one"
2) "two"
127.0.0.1:6379> ZINTERCARD 2 zset1 zset2
(integer) 2
127.0.0.1:6379> ZINTERCARD 2 zset1 zset2 LIMIT 1
(integer) 1

see how ZINTER spills the whole tea and ZINTERCARD is like "it's 2, bye"? and with LIMIT 1 she doesn't even finish counting — she already knows it's 1 and dips. main character energy, no cap 🫶

SEE ALSO 👑

and that's the whole page, bestie!! 🦋 this was Valkey manual version 9.0.0, dated 2025-10-21, and you were reading ZINTERCARD(3valkey). go count something. slay 💖✨👑

📦 where this page comes from