Mean
syntax
- mean(a)
- mean(a, relation)
definition
- mean(a) results in a parameter with the average of the non null values of attribute a.
- mean(a, relation) results in a an attribute with the average 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.
applies to
- attribute a with Numeric value-type
- 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 unit of argument a and relation must match.
example
parameter<uint32> meanNrInh := mean(City/NrInhabitants); result = 375
attribute<uint32> meanNrInhRegion (Region) := mean(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
| meanNrInhRegion |
|---|
| 550 |
| 512 |
| 300 |
| 200 |
| null |
domain Region, nr of rows = 5