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ZINTERSTORE

Computes the intersection of multiple sorted sets and stores the resulting sorted set in a new key. The scores of the elements in the resulting sorted set are computed according to the specified options.

Syntax​

ZINTERSTORE destination numkeys key [key ...] [WEIGHTS weight [weight ...]] [AGGREGATE SUM|MIN|MAX]

Parameters​

  • destination: The key where the result of the intersection will be stored.
  • numkeys: The number of sorted sets involved in the operation.
  • key: The name of each sorted set involved in the operation.
  • WEIGHTS: Optional. Specifies a multiplication factor for each sorted set’s scores. If not specified, the default weight is 1 for all sets.
  • AGGREGATE: Optional. Specifies how to combine the scores of elements that exist across multiple sets. The options are SUM (default), MIN, or MAX.

Details​

  • Available since: 2.0.0
  • Time complexity: O(N*K + M log(M)) where N is the size of the input sorted sets, K is the number of sets, and M is the number of elements in the result.
  • ACL categories: @write, @sortedset, @slow

The ZINTERSTORE command computes the intersection of the specified sorted sets and stores the result in the destination key. The resulting set consists of members that are present in all the specified sets. The score of each member in the result is computed based on the WEIGHTS and AGGREGATE options.

Examples​

Basic Usage​

Assume we have three sorted sets:

ZADD set1 1 "a" 2 "b" 3 "c"
ZADD set2 1 "b" 2 "c" 3 "d"
ZADD set3 1 "c" 2 "d" 3 "e"

To find the intersection of these sets and store the result in resultset:

ZINTERSTORE resultset 3 set1 set2 set3

After running this command, the resultset will contain:

ZRANGE resultset 0 -1 WITHSCORES

This will return:

1) "c"
2) "6"

Using the WEIGHTS Option​

To multiply the scores of set1 by 2, set2 by 3, and set3 by 1 before computing the intersection:

ZINTERSTORE resultset 3 set1 set2 set3 WEIGHTS 2 3 1

Using the AGGREGATE Option​

To find the intersection but keep the minimum score from the sets for each member:

ZINTERSTORE resultset 3 set1 set2 set3 AGGREGATE MIN

Edge Cases​

  • If the destination key already exists, it will be overwritten with the new result.
  • If the intersection is empty, the destination key will be set to an empty sorted set.
  • If any of the input keys do not exist, they are treated as empty sets.
  • If any of the keys refer to non-sorted set data types, an error is returned.

RESP2/RESP3 Reply​

  • Integer reply: the number of elements in the resulting sorted set stored at the destination key.