ZDIFFSTORE(3valkey)

📦
version 9.0.6 · 2 versions
, in fedora 44

💖 ZDIFFSTORE 💖

okay so bestie, welcome to the Valkey Command Manual ✨ this one lives in section 3valkey and it's genuinely one of my faves, no cap.

✨ NAME ✨

zdiffstore — stores the difference of multiple sorted sets in a key. like, it does the math and then parks the answer in a whole new key. obsessed. 🎀

🌸 SYNOPSIS 🌸

ZDIFFSTORE destination numkeys key [key...]

🦋 DESCRIPTION 🦋

So here's the vibe: ZDIFFSTORE computes the difference between the first input sorted set and all the successive input sorted sets, then stores the result in destination. 💅

The total number of input keys is specified by numkeys. yes girl, you have to tell it how many. it can't read your mind (yet). 😭

Keys that don't exist? they're considered to be empty sets. no drama, no error, just an empty vibe. 🫶

And if destination already exists, it gets overwritten. so like… gone. replaced. main character energy only. 👑

💌 REPLY 💌

valkey-protocol(7) Integer reply: the number of members in the resulting sorted set at destination. so you get a lil count back, cute. ⭐

🔥 COMPLEXITY 🔥

O(L + (N-K)log(N)) worst case, where:

  • L is the total number of elements in all the sets,
  • N is the size of the first set,
  • K is the size of the result set.

not me actually respecting the worst case 😭 it's giving "we've thought about this" fr fr.

🎀 ACL CATEGORIES 🎀

@slow @sortedset @write

three whole categories, slay. 💖

🌈 HISTORY 🌈

  • Available since: 6.2.0

an icon from day one honestly.

✨ EXAMPLES ✨

okay bestie, watch this, it's so satisfying:

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 zset1 3 "three"
(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> ZDIFFSTORE out 2 zset1 zset2
(integer) 1
127.0.0.1:6379> ZRANGE out 0 -1 WITHSCORES
1) "three"
2) "3"

see how "three" was the only one that survived the difference?? the way it ate and left no crumbs 🍓

💜 SEE ALSO 💜

like a whole friend group of sorted-set commands, iykyk. 🧚

go read the whole squad, bestie. sorted sets are lowkey the moment. 🙈

okay byeeee, this page was Valkey 9.0.0, dated 2025-10-21 — drink water, use ZDIFFSTORE responsibly, and remember: overwriting a key is forever 💀🫶

📦 where this page comes from