presto-main/src/main/java/io/prestosql/operator/scalar/DateTimeFunctions.java/DateTimeFunctions/fromUnixTime
class DateTimeFunctions:    @ScalarFunction("from_unixtime")
    @SqlType(StandardTypes.TIMESTAMP)
    public static long fromUnixTime(@SqlType(StandardTypes.DOUBLE) double unixTime)
    {
        return Math.round(unixTime * 1000);
    }