Xbasic

LAST Function

Syntax

Last_Value as A = last(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.

over

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 last of subexpression over group 'over' sampled each group 'each'

Discussion

LAST() returns the last value of the Expression evaluated for a group of records. The expression is evaluated for the last record in the sub-group that is related to the group's current record, and then the value is returned. For example, to summarize the line-items in an invoice set, the Group parameter might be GRP ->INVOICE 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 INVOICE 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. If you use this summary function in a report layout, the group name can be the name assigned to any of the report's grouping levels.

Example 

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
>
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
>
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 a particular invoice's last line-item record, use the following expression:

'if the current INV_NO is "I102"
? last(INV_ITEM->AMOUNT, GRP ->INVOICE, GRP ->INV_ITEM)
= 62.25

To determine the last record from the total number of INVOICE records, the expression is:

? last(INVOICE->INV_NO, GRP ->GRAND)
= I105

See Also