The CAST function converts a value expression to another data
    type. The source and target columns can be of any data type
    except LIST OF BYTE VARYING.

    If you convert to an INTERVAL data type, you must specify a
    single interval qualifier field, and the source must be a numeric
    value (fixed or floating) or a compatible INTERVAL data type.
    For information on interval qualifiers, see the Data_Types HELP
    topic.

    You can also convert from a single interval qualifier field to a
    numeric type (fixed or floating).

    If you convert a TIMESTAMP literal using the CAST function, SQL
    puts a separating space character (SQL92) between the date-body
    and the time-body of the TIMESTAMP literal. For more information
    on TIMESTAMP literals, see Date Time Literals.

    The CAST function allows you to convert host language variables
    into date-time values. You can also use the CAST function to
    express dates in VMS format as ANSI format dates (using the
    syntax CAST(date-vms-value-expr AS DATE ANSI)) to do date
    arithmetic using DATE VMS data.