frequency_table

Aggregation functions frequency_table

syntax

frequency_table(a)
frequency_table(a, relation)

definition

frequency_table(a) results in a Parameter with a string listing all non-Null values of Attribute a together with how often each value occurs, separated by “; “.
frequency_table(a, relation) results in an attribute with such strings, one per partition defined by relation. The Domain unit of the resulting attribute is the Values unit of the relation. Each partition string contains the value-count pairs for the non-null values of a belonging to that partition.

description

The result per partition is a string of the form value1: count1; value2: count2; ..., where:

values are listed in ascending order (the order defined by the Values unit of attribute a),
only values with a non-zero count are included,
null values in a are excluded from the counts.

To include null values in the frequency table, use frequency_table_with_null instead.

applies to

attribute a with any scalar Value type
relation with value type of the group CanBeDomainUnit

conditions

The domain of Argument a and relation must match.

since version

14.4.0

example

parameter<string> freqLifeStyleCode := frequency_table(City/LifeStyleCode);
// result = "0: 2; 1: 3; 2: 1"

attribute<string> freqLifeStyleCodePerRegion (Region) := frequency_table(City/LifeStyleCode, City/Region_rel);

City/LifeStyleCode	City/Region_rel
2	0
0	1
1	2
0	1
1	3
1	null
null	3

domain City, nr of rows = 7

freqLifeStyleCodePerRegion
“2: 1”
“0: 2”
“1: 1”
“1: 1”
”“

domain Region, nr of rows = 5

City 6 (LifeStyleCode = null) is excluded. City 5 (Region_rel = null) is excluded from all groups.