Specify COMP at the select- or omit-field level

At the select/omit-field level, you can specify a field name, a value, or *NULL for the parameter.

If the select/omit field is a binary character field, the field-name parameter must also be a binary character field. The comparisons for binary character select/omit fields also need to take the actual lengths of the operands into consideration. The operands will only compare as equal if the actual lengths of the operands are equal. Shorter operands will be considered less than the longer operands when they are equal up to the length of the shorter operand.

If you specify a value, the following rules apply:

If you are defining a character field, specify a character constant or a hexadecimal character string.
Specify character strings with single quotation marks (see Example 1 in the COMP (Comparison) keyword for physical and logical files topic).

Specify hexadecimal character strings as an X followed by a combination of the digits 0 through 9 and the letters A through F, enclosed in single quotation marks ('). The number of hexadecimal digits in single quotation marks must be exactly twice the specified length of the field (see Example 2 in the COMP (Comparison) keyword for physical and logical files topic).
If you are defining a numeric field, specify a numeric string (digits 0 through 9 specified without single quotation marks) as shown in example 2.
If you are defining a date field, specify a valid date in the same format specified on the DATFMT keyword and use the same separator as specified on the DATSEP keyword.
For example, COMP(EQ '12/15/91') is the default value if *MDY is specified for DATFMT and '/' is specified for DATSEP.
If you are defining a time field, specify a valid time in the same format specified on the TIMFMT keyword and use the same separator as specified on the TIMSEP keyword.
For example, COMP(EQ '11.00.00') is the default value if *ISO is specified for TIMFMT. The default separator for *ISO is a period (.).
If you are defining a timestamp field, you must specify the default value in the following format:
```
COMP(EQ 'YYYY-MM-DD-HH.MM.SS.UUUUUU')
```

If you specify *NULL, the relational operator must be EQ or NE.

COMP selects or omits records retrieved from the physical file on which this logical file is based when your program sends an input operation to the record format you are defining. The operating system selects or omits records as a result of testing the value of the select/omit fields against the value you specify, the value of the field whose name you specify, or the null value (if *NULL was specified).