VMS Help MERGE, Specification File Qualifiers, /KEY  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Specification File Qualifier

    Identifies key field names, specifies sorting order, and changes
    the order of records in the output file.

    Formats

      /KEY=field-name

      /KEY=(field-name,order)

      /KEY=([IF condition-name THEN value ELSE]...value [,order])

1 - Qualifier Values

 field-name

    Specifies the name of the key field. The field-name has been
    previously specified in a /FIELD qualifier.

 order

    Specifies the order of the sort. The ASCENDING option specifies
    ascending order for a sort or merge operation. This option is the
    default. The DESCENDING option specifies descending order for a
    sort or merge operation.

 value

    Specifies the key. The value can be a constant or a field-name
    that has been defined in a /FIELD qualifier.

2 - Full Description

    If you are sorting on the entire record using character data, you
    do not need to specify your key field. Otherwise, specify a /KEY
    qualifier for each of the keys, in the order of their priority.
    You can sort on as many as 255 key fields.

    There are three ways to use the /KEY qualifier:

    o  To identify the key field name.

    o  To identify the key field name and to specify sorting order.
       In this case, enclose the field name and the order option in
       parentheses.

    o  As a conditional qualifier, to change the order of records
       in the output file. First, specify a condition name in a
       /CONDITION qualifier, and set up a test for what meets
       that condition. Then, specify the relative order in a /KEY
       qualifier of the form:

       /KEY=(IF condition-name THEN value ELSE value)

       You can use any values to specify the relative order of the
       records.

3 - Examples

    1./FIELD=(NAME=SALARY,POSITION:10,DIGITS:8,DECIMAL)
      /KEY=(SALARY,DESCENDING)

      This /KEY qualifier specifies that the key field is SALARY and
      that the sorting order is descending.

    2./FIELD=(NAME=ZIP,POSITION:20,SIZE:6)
      /CONDITION=(NAME=LOCATION,
                  TEST=(ZIP EQ "01863"))
      /KEY=(IF LOCATION THEN 1
            ELSE 2)

      In this example, all the records with the zip code 01863 are
      to appear at the beginning of the sorted output file. The
      conditional test LOCATION (defined in a /CONDITION qualifier)
      is on the ZIP field (named in a /FIELD clause). The values of
      1 and 2 in this /KEY clause signify a relative order for those
      records that satisfy the condition and those that do not.