min_alldefined
Aggregation functions minimum alldefined
Note: this function will be available in GeoDMS 20.10.0 or later.
syntax
- min_alldefined(a)
- min_alldefined(a, relation)
definition
A variant of the minimum aggregation that only results in a value when all aggregated values are defined:
- min_alldefined(a) results in a Parameter with the minimum of the values of Attribute a, or Null as soon as any value of a is null (and for an empty domain).
- min_alldefined(a, relation) results in an attribute with, per group of relation, the minimum of the values, or null for groups containing any null value (and for empty groups). The Domain unit of the resulting attribute is the Values unit of the relation.
Where no null value is involved, min_alldefined equals Min. It is the aggregation analogue of the elementwise min_elem_alldefined function.
applies to
- attribute a with Numeric or Point value type (unlike Min, not defined for string data)
- relation with value type of the group CanBeDomainUnit
conditions
- The values unit of the resulting data item should match with regard to value type and Metric with the values unit of attribute a.
- The domain of Argument a and relation must match.
example
attribute<uint32> minNrInhRegion (Region) := min_alldefined(City/NrInhabitants, City/Region_rel);
| City/NrInhabitants | City/Region_rel |
|---|---|
| 550 | 0 |
| 525 | 1 |
| 300 | 2 |
| 500 | 1 |
| 200 | 3 |
| 175 | null |
| null | 3 |
domain City, nr of rows = 7
| minNrInhRegion |
|---|
| 550 |
| 500 |
| 300 |
| null |
| null |
domain Region, nr of rows = 5
Region 3 contains a null value and region 4 has no cities, so both result in null.