Report Calculated Fields
In general, each column of a report will contain values for a selected data field. However, here you can specify calculations that will derive the content of a column. You can only undertake calculations on columns that show on the report and cannot use a calculated field as part of a calculation.
Any existing entries are listed and you can click 
to create a further entry at the end of the list or 
to remove an entry that is not required.
For each entry, which will define a particular column, input or select details at each field:
•Title provides a title for the data that results from the calculation
•Expression can either be input or you can click 
to use the Expression Builder, which is described next.
•Evaluate Null as 0 indicates, if checked, that an expression that fails to deliver a valid value will have the value set to zero.
•Type determines how the result of the calculation is to be presented; a type of Decimal will require the input of the number of decimal places.
Indicate how the resulting value is to be shown in sub-totals and totals on change of the fields specified under Group Rows by (selections will vary depending on the specified Type):
o Sum — total of the accumulated field values
o Min/Max — the lowest or highest value within the group
o Expression — use the calculated field expression against summarized values to derive a total
o Count — the number of records since the last change of group value
o Average — the total of accumulated field values divided by the number of rows
o Unique Count — the number of records since the last change of group value, ignoring those with duplicated field content (such as the same name).
Check Cumulative if the relevant value is to be accumulated through subsequent sub-totals for a grand total or is to be cleared down to zero on each change of group value.
o Heading Group is a selected or entered name that is to appear at the head of several grouped columns with the same heading group name (such as grouping several types of cost).
