Syntax options:

       FROM statement-string
       FROM parameter

    Specifies the SQL statement to be prepared for dynamic execution.
    You either specify the statement string directly enclosed in
    single quotation marks, or in a parameter (a host language
    variable in a precompiled PREPARE statement or a formal parameter
    in a PREPARE statement that is part of an SQL module language
    procedure) that contains the statement string.

    Whether specified directly or by a parameter, the statement
    string must be a character string that is a dynamically
    executable SQL statement. If you specify the statement string
    directly, the maximum length is 1,024 characters. If you specify
    the statement string as a parameter, the maximum length of the
    statement string is 65,535 characters.

    The form for the statement is the same as for embedded SQL
    statements, except that:

    o  You must not begin the string with EXEC SQL.

    o  In places where SQL allows host language variables in an
       embedded statement, you must specify parameter markers
       instead.

    If you try to prepare an invalid statement, you will find a value
    in the SQLCODE, the SQLCODE field of the SQLCA, or the SQLSTATE
    status parameter indicating an error.

    The values returned to the SQLCODE field are described in the
    Oracle Rdb SQL Reference Manual. Check the message vector to
    see which error message was returned. If necessary, refer to the
    error message explanations and user actions located by default in
    the SQL HELP ERRORS.

    Parameter markers are question marks (?)  that denote parameters
    in the statement string of a PREPARE statement. Parameter markers
    are replaced by values in parameters or dynamic memory when the
    prepared statement is executed by an EXECUTE or OPEN statement.