Count

aggregation-functions count

syntax

  • count(a)
  • count(a, relation)

definition

  • count(a) results in an uint32 parameter with the number of non null values of attribute a.
  • count(a, relation) results in a an uint32 attribute with the number of 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 or Point value type
  • relation with value type of the group CanBeDomainUnit

conditions

The domain unit of arguments a and relation must match.

example 

1. parameter<uint32> countNrInh                := count(City/NrInhabitants); result = 6
2. attribute<uint32> countNrInhRegion (Region) := count(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

countNrInhRegion
1
2
1
1
0

domain Region, nr of rows = 5

see also