SetAgg¶

A SetAgg aggregator value variable (SetAgg<T>) aggregates all inputs into a set that contains only unique values, where T represents the data type of the input values. To aggregate a list of input values with duplicates, see ListAgg.

Declaration syntax¶

diagramsource

set_agg_declaration

set_agg_declaration ::=
'NODE'? 'VALUE' aggregator_value_variable 'SetAgg' '<' ('INT8'|'INT16'|'INT32'|'INT64'|'FLOAT'|'DOUBLE'|'STRING') '>'

For information about the parameters in the declaration syntax, see Parameters.

Initial value¶

As indicated in the declaration syntax, an initial value must not be specified during declaration.

Input type and supported operations¶

The input type must be T, which is specified during declaration.

Both assignment and aggregation operations are supported.

Return type¶

SetAgg<T> -> LIST<T>

The return type is LIST<T>, with unique elements of the same type as the type T specified during declaration.

Member functions¶

This section introduces the member functions supported by SetAgg<T>.

size()¶

Returns the number of unique elements in the set held by a SetAgg aggregator value variable.

Function signature¶

size() -> UINT64

clear()¶

Removes all elements from the set held by a SetAgg aggregator value variable.

Function signature¶

clear() -> VOID

contains_key()¶

Returns true if the specified value exists in the set held by a SetAgg aggregator value variable; otherwise, it returns false.

Function signature¶

contains_key(value: T) -> BOOL

Examples¶

The following examples are based on the temporary graph #movie_temporary_graph created in CREATE TEMPORARY GRAPH.

Global SetAgg aggregator value variables¶

'''
USE #movie_temporary_graph {
  VALUE global_set_1 SetAgg<INT>
  VALUE global_set_2 SetAgg<INT>
  SET @global_set_1 += 3    // set: {3}
  SET @global_set_1 += 7    // set: {3, 7}  
  SET @global_set_1 += 3    // set: {3, 7} (duplicate ignored)
  SET @global_set_1 += 5    // set: {3, 7, 5}
  LOG_INFO("@global_set_1: ", @global_set_1)

  // Assignment from empty LIST
  SET @global_set_1 = []  // Clear the set
  LOG_INFO("Set from empty LIST:", @global_set_1)  // output: []

  // Assignment from a LIST 
  SET @global_set_1 = [1, 2, 2, 3, 1, 4]  // set: {1, 2, 3, 4}
  LOG_INFO("Set from LIST assignment: ", @global_set_1)

  SET @global_set_2 += 3  // global_set_2: {3}
  SET @global_set_2 += 4  // global_set_2: {3,4}
  LOG_INFO("@global_set_2: ", @global_set_2)

  // Assignment from another SetAgg
  SET @global_set_1 = @global_set_2        // global_set_1: {3,4}
  LOG_INFO("After assignment from set_2: ", @global_set_1)

  // Aggregation from another SetAgg
  SET @global_set_1 += @global_set_2       // global_set_1: {3,4}
  LOG_INFO("After aggregation from set_2: ", @global_set_1)

  // Member functions
  SET @global_set_2.clear()  // Clear the set 
  LOG_INFO("Clear the set: ", @global_set_2)      // Output: []
  LOG_INFO("Size: ", @global_set_1.size())      // Output: 4
  LOG_INFO("Contains 4: ", @global_set_1.contains_key(4))      // Output: true
  LOG_INFO("Contains 100: ", @global_set_1.contains_key(100))      // Output: false
}
'''

Return:

Log:
2025-08-21T02:18:53.175811 INFO  - @global_set_1: [5,7,3]
2025-08-21T02:18:53.176426 INFO  - Set from empty LIST:[]
2025-08-21T02:18:53.176812 INFO  - Set from LIST assignment: [4,3,2,1]
2025-08-21T02:18:53.177273 INFO  - @global_set_2: [4,3]
2025-08-21T02:18:53.177556 INFO  - After assignment from set_2: [3,4]
2025-08-21T02:18:53.177808 INFO  - After aggregation from set_2: [3,4]
2025-08-21T02:18:53.178056 INFO  - Clear the set: []
2025-08-21T02:18:53.178199 INFO  - Size: 2
2025-08-21T02:18:53.178400 INFO  - Contains 4: true
2025-08-21T02:18:53.178600 INFO  - Contains 100: false

Node-attached SetAgg aggregator value variables¶

'''
USE #movie_temporary_graph {
  NODE VALUE node_set SetAgg<DOUBLE>
  MATCH (a@User WHERE a.id IN [1,3,4])-[w@Watch]->(b@Movie)
  PER PATH {
    // For each matched path, add the movie ID to the corresponding user's set
    SET a.@node_set += b.id
  }
  PER NODE (a) {
    LOG_INFO("a.id: ", a.id, " a.@node_set: ", a.@node_set)
  }
}
'''

In the preceding example, a node-attached SetAgg aggregator value variable node_set of type SetAgg<DOUBLE> is declared to hold a set of unique movie IDs for each user.

Return:

Log:
2025-08-12T09:05:22.315257 INFO  - a.id: 1 a.@node_set: [10,104,11,497,252,601,100,651,473]
2025-08-12T09:05:22.315257 INFO  - a.id: 3 a.@node_set: [152,473]
2025-08-12T09:05:22.315257 INFO  - a.id: 4 a.@node_set: [346,99,648,144,637,146,671,10,104,11,252,473]