JOIN

    To create a new database file by merging selected records and fields
    from two work areas.

Syntax

    JOIN WITH <alias>/(<expC1>) TO <file>/(<expC2>) FOR <condition>
    [FIELDS <field list>]

Argument

    <alias> is the work area to merge with records from the current work
    area.

    <file> is the name of the target database file.

Options

    For: The FOR <condition> selected only records meeting the
    specified condition.

    Fields: The <field list> is the projection of fields from both work
    areas into the new database file.  To specify any fields in the
    secondary work area, reference them with the alias.  if the FIELDS
    clause is not specified, all fields from the primary work area will be
    included in the target database file.

Usage

    JOIN is a project of fields and a selection of records from two work
    areas that forms a new database file based on a general condition.
    JOIN works by making a complete pass through the secondary work area
    for each record in the primary work area evaluating the condition for
    each record processed in the secondary work area.  When the condition
    is true (.T.), a new record is created in the target database file.

    Note that the number of records processed will be the RECCOUNT() of the
    primary work area times the RECCOUNT() of the secondary work area.  For
    example, if you have two database files with 100 records each, the
    number of records JOIN processes is the equivalent of sequentially
    processing a single database file of 10,000 records.  All of which
    necessitates the maxim, "use this command with prudence."