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

• pcount