topKWeighted

Introduced in: v1.1.0 Returns an array of the approximately most frequent values in the specified column. The resulting array is sorted in descending order of approximate frequency of values (not by the values themselves). Additionally, the weight of the value is taken into account. See Also

Syntax

topKWeighted(N)(column, weight)
topKWeighted(N, load_factor)(column, weight)
topKWeighted(N, load_factor, 'counts')(column, weight)

Parameters

N — The number of elements to return. Default value: 10. UInt64
load_factor — Optional. Defines, how many cells reserved for values. If uniq(column) > N * load_factor, result of topK function will be approximate. Default value: 3. UInt64
counts — Optional. Defines whether the result should contain an approximate count and error value. Bool

Arguments

column — The name of the column for which to find the most frequent values. - weight — The weight. Every value is accounted weight times for frequency calculation. UInt64

Returned value Returns an array of the values with maximum approximate sum of weights. Array Examples Usage example

Query

SELECT topKWeighted(2)(k, w) FROM
VALUES('k Char, w UInt64', ('y', 1), ('y', 1), ('x', 5), ('y', 1), ('z', 10));

Response

┌─topKWeighted(2)(k, w)──┐
│ ['z','x']              │
└────────────────────────┘

With counts parameter

Query

SELECT topKWeighted(2, 10, 'counts')(k, w)
FROM VALUES('k Char, w UInt64', ('y', 1), ('y', 1), ('x', 5), ('y', 1), ('z', 10));

Response

┌─topKWeighted(2, 10, 'counts')(k, w)─┐
│ [('z',10,0),('x',5,0)]              │
└─────────────────────────────────────┘

See Also

​topKWeighted

topKWeighted