The SQL Asterisk character (*) may be specified by the user as the argument to a Count aggregate or Windowed Count Ordered Analytical function. It represents the fact that all rows should be counted, not just those with non-null values in a particular column. When dragging an Asterisk operator into a variable, the following tree element is created.
Variable Creation > Input > Variables: SQL Elements pane - Other > Asterisk
The SQL Asterisk character (*) is valid within a COUNT aggregate and windowed aggregate function.
There are no special properties for the Asterisk operator.