Eq

ordering-functions equals (==)

syntax

  • eq(a, b)
  • a == b

definition

eq(a, b) or 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.

description

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

applies to

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

conditions

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

example 

1. attribute<bool> AisB (CDomain) := eq(A, B);
2. attribute<bool> AisB (CDomain) := A == B;
A B AisB
0 0 True
1 2 False
2.5 2.5 True
-100 100 False
999 -999 False
null 0 False
null null False
0 null False
null 100 False
100 null False

CDomain, nr of rows = 10

see also