Specifications

Four examples
630 InfoMaker
Within an expression, a function can return other datatypes (such as boolean,
date, or integer), but the final value of an expression is converted to one of
these datatypes.
Restrictions for
aggregate functions
An aggregate function is a function (such as Avg, Max, StDev, and Sum) that
operates on a range of values in a column. When you use an aggregate function,
some restrictions apply. You cannot use an aggregate function:
• In a filter
• In a validation rule
• As an argument for another aggregate function
When you use aggregate functions, they cancel the effect of setting Retrieve
Rows As Needed. To do the aggregation, the report always retrieves all rows.
Formatting for the
locally correct display
of numbers
No matter what country you are creating objects and developing an application
in, you must use U.S. number notation in numbers or number masks in display
formats, edit masks, and DataWindow and InfoMaker expressions. This means
that when you specify a number or number mask, use a comma as the
thousands delimiter and period for the decimal place.
Numbers display appropriately in whatever countries you deploy applications
in. At runtime, the locally correct symbols for numbers display (because the
international Control Panel settings are used) when numbers are interpreted.
For example, in countries where comma represents the decimal place and
period represents thousands, users see numbers in those formats at runtime.
For information about the locally correct display of dates and day names, see
String on page 746 and DayName on page 674.
Four examples
Example 1: counting null values in a column
A null value is a marker used to fill a place in a column where data is missing
for any reason. The value might not be applicable, or it might be missing or
unknown. When a database table is created, each column in the table either
allows null values or does not allow them. The column or set of columns that
define the primary key cannot allow null values. Sometimes it is useful to know
how many null values there are in a particular column.