Xbasic

RUN_AVERAGE Function

Syntax

Running_Average_Value as A = run_average(A subexpr[,G over[,G each])

Arguments

subexpr

Any valid expression that includes a field or a combination of fields from the current table or set that specifies what you want to examine. Any type

over

Group Optional. When to use the function (instead of on every record).

each

Optional. When to reset the value produced by the function to 0 (instead at the end of all records). The Group and Sub_Group are optional parameters that define the range of records to summarize, and may or may not be required, depending upon the context of the summary calculation. Possible values for GRP >Group and GRP >Sub_Group include:

GRAND (all records)
The name of the current table
The name of a table in the current set
The name of a grouping level that is defined in a report layout
DETAIL (over the records in the detail section)

Description

Get the running average of subexpression over group 'over' sampled each group 'each'

Discussion

RUN_AVERAGE() is used in the Detail section of a report to return the running average of the Expression evaluated from the first record to the current record related to the group. The expression is evaluated from the sub-group's first record to the current record; the resulting values are added together and the average value is returned. For example, to summarize the line-items in an invoice set, the Group parameter might be GRP ->INV_HEAD and the Sub_Group parameter GRP >INV_ITEM. This means the Summary operation includes only those child records in INV_ITEM related to the current parent record in the Inv_head table. To summarize all the records in a table or set, use the name GRAND as the Group name. The Group GRP >GRAND and Sub_Group GRP >INV_ITEM produce a summary result based on all invoices. This function is a report writer function, not intended for table level field rules or other expressions. While the function may perform in some areas outside of the report writer, its use there is not supported.

Assume that an invoicing set consists of two tables. One holds the invoices ( INVOICE ), and the other holds each invoice's line-items ( INV_ITEM ):

INVOICE: Description
INV_NO: CUST_ID and INV_TOTAL
I100: C001 10.00
I101: C003 25.50
I102: C001 100.75
I103: C004 32.50
I104: C002 110.25
I105: C005 98.35

INV_ITEM: Description
INV_NO: AMOUNT
I100: 4.50
I100: 5.50
I101: 25.50
I102: 3.25
I102: 35.25
I102: 62.25
I103: 32.50
I104: 110.25
I105: 98.35

INVOICE is related to INV_ITEM through a one-to-many link on the INV_NO field. To find the running average of line-item records, use the following expression:

run_average(INV_ITEM->AMOUNT) -> 11.83, if the current INV_NO is "I101"

Limitations

This function is a report writer function, not intended for table level field rules or other expressions.