Eq_or_both_null - ObjectVision/GeoDMS GitHub Wiki

Ordering functions equals or both values null

• eq_or_both_null(a, b)

eq_or_both_null(a, b) results in a boolean data item indicating if the values of data item a are equal to the corresponding values of data item b or if both corresponding values are null.

The comparison between two missing values (null == null) results in the value True.

Data items with Numeric, Point, string or bool value type

1. Domain of the arguments must match or be void (literals or parameters can be compared to data items of any domain).
2. Arguments must have matching:
   • value type
   • metric

attribute<bool> AisB (CDomain) := eq_or_both_null(A, B);

CDomain, nr of rows = 10

• eq