Max

Aggregation functions max(imum)

syntax

• max(a)
• max(a, relation)

definition

• max(a) results in a parameter with the maximum of the non null values of attribute a.
• max(a, relation) results in an attribute with the maximum of the non null values of attribute a, grouped by relation. The domain unit of the resulting attribute is the values unit of the relation.

description

The max function is not defined for boolean data items, use the all function instead.

If there are no values to be aggregated for a group, the resulting value will be the minimum value for the value type of attribute a (in the example: 0, the minimum value for the value type: uint32) .

applies to

• attribute a with Numeric, Point or string value type
• relation with value type of the group CanBeDomainUnit

conditions

1. The values unit of the resulting data item should match with regard to value type and metric with the values unit of attribute a.
2. The domain of argument a and relation must match.

example

parameter maxNrInh := max(City/NrInhabitants); result = 550 parameter maxCity  := max(City/CityName)     ; result = ‘Utrecht’ attribute maxNrInhRegion    (Region) := max(City/NrInhabitants, City/Region_rel);   attribute maxCityNameRegion (Region) := max(City/CityName, City/Region_rel);   

City/NrInhabitants	City/CityName	City/Region_rel
550	Amsterdam	0
525	Rotterdam	1
300	Utrecht	2
500	DenHaag	1
200	Eindhoven	3
175	Haarlem	null
null	null	3

domain City, nr of rows = 7

maxNrInhRegion	maxCityNameRegion
550	Amsterdam
525	Rotterdam
300	Utrecht
200	Eindhoven
0

domain Region, nr of rows = 5

see also

• min
• max_index