A quoted character string literal is a string of printable
    characters enclosed in single quotation marks. The maximum length
    of a character string is 1,024 octets. An unqualified character
    string must contain characters only from the literal character
    set of that session.

    The printable ASCII characters consist of:

    o  Uppercase alphabetic characters:

       A-Z

    o  Lowercase alphabetic characters:

       a-z

    o  Numerals:

       0-9

    o  Special characters:

       ! @ # $ % ^ & * ( ) - _ = + ` ~

       [ ] { } ; : " \ | / ? > < . ,

    For a list of the printable characters for DEC_MCS, see the
    OpenVMS documentation for users; for a list of printable
    characters for the other supported character sets, see the
    standard for that character set.

    Use a pair of single quotation marks to enclose a character
    string literal. If you use double quotation marks, an
    informational message is displayed, indicating that double
    quotation marks are nonstandard. Double quotation marks are
    passed as delimited identifiers if the quoting rules are set
    to ANSI/ISO SQL.

1  –  Qualified

    You can use a quoted character string literal qualified by
    the name of a character set. The character string must contain
    characters only from the named character set.

    A string literal qualified by a character set begins with an
    underscore (_),  followed by the name of a supported character
    set, and a quoted string. No blank spaces are allowed outside of
    the literal.

    The following example shows how to qualify character strings with
    DEC_MCS and with DEC_KANJI:

    _DEC_MCS'Blue'

    _DEC_KANJI'Blue'

    You can use a national character string literal, which is a
    quoted character string literal qualified by the national
    character set. The character string must contain characters only
    from the national character set.

    A national character string literal begins with the letter N
    followed by a quoted string. No blank spaces are allowed outside
    of the literal.

    The following example shows how to qualify a character string
    with the national character set:

    N'Blue'