In ClarisWorks and ClarisImpact, to calculate and display the name of the month which has been entered into a date field, you must use the Month function to get the month number, then use the MONTHNAME function on that value.
ClarisWorks Database:
Here is a calculation to extract the name of the month from a date field:
Month = (Calculation, Text result) = MONTHNAME(MONTH('DateField'))
ClarisWorks Spreadsheet or ClarisImpact Table:
The formula to accomplish the same task, assuming the date is in cell A1 would be:
=MONTHNAME(MONTH(A1))
If you do not use this structure, and attempt to use the MONTHNAME function directly upon a date, you will get an #ERROR! result in the field. (#ARG! in a spreadsheet cell). This is because the MONTHNAME function works on a integer number value from 1 to 12 inclusive, while ClarisWorks stores dates internally as serial numbers representing the number of days since January 1, 1904.