Chapter 2: DataWindow Expression Functions

First

Description

Reports the value in the first row in the specified column.

Syntax

First ( column { FOR range  { DISTINCT { expresn  {, expres2 {, ... } } } } } )

Argument	Description
column	The column for which you want the value of the first row. Column can be a column name or a column number preceded by a pound sign (#). Column can also be an expression that includes a reference to the column.
FOR range (optional)	The data that will be included when the value in the first row is found. For most presentation styles, values for range are: ALL — (Default) The value in the first of all rows in column. GROUP n — The value in the first of rows in column in the specified group. Specify the keyword GROUP followed by the group number: for example, GROUP 1. PAGE — The value in the first of the rows in column on a page. For Graph objects, specify one of the following: GRAPH — The value in the first row in column in the range specified for the Rows option.
DISTINCT (optional)	Causes First to consider only the distinct values in column when determining the first value. For a value of column, the first row found with the value is used and other rows that have the same value are ignored.
expresn (optional)	One or more expressions that you want to evaluate to determine distinct rows. Expresn can be the name of a column, a function, or an expression.

Returns

The datatype of the column. Returns the value in the first row of column. If you specify range, First returns the value of the first row in column in range.

Usage

If you specify range, First determines the value of the first row in column in range. If you specify DISTINCT, First returns the first distinct value in column, or if you specify expresn, the first distinct value in column where the value of expresn is distinct.

For graphs, you do not select the range when you call the function. The range has already been determined by the Rows setting on the Data property page (the Range property), and the aggregation function uses that range. Settings for Rows include the following:

For the Graph presentation style, Rows is always All.
For Graph controls, Rows can be All, Page, or Group.

Not in validation rules or filter expressions You cannot use this or other aggregate functions in validation rules or filter expressions.

Using an aggregate function cancels the effect of setting Retrieve Rows As Needed in the painter. To do the aggregation, a DataWindow object or a report always retrieves all rows.

Examples

Example 1

This expression returns the first value in column 3 on the page:

First(#3 for page)

Example 2

This expression returns the first distinct value in the column named dept_id in group 2:

First(dept_id for group 2 DISTINCT)

Example 3

This expression returns the first value in the column named dept_id in group 2:

First(dept_id for group 2)