firstval

firstval — aggregate function to return the first value from a specified column.

SYNOPSIS

firstval (expr)

DESCRIPTION

This function returns the first value in the range of values returned by its query predicate.

Expression expr must contain the name of a column in a LiveView table. The returned first value is of the same type as the specified column.

If the query returns no rows, the aggregate returns null when group-by is not specified, and no rows when a group-by is specified.

EXAMPLE

This example shows a simple use of the firstval() function.

  1. In LiveView Desktop connected to a server running the Hello LiveView sample, select the ItemsSales table from the Tables pane of the LiveView Tables view.

  2. In the Select field, enter: 

    firstval(Item) as First

  3. Make sure the Query field is empty.

  4. Click Open Query.

The query results open in a grid view.

SEE ALSO

This LiveView aggregate function is based on the firstval aggregate function in the StreamBase expression language.