presto-main/src/main/java/io/prestosql/operator/scalar/MathFunctions.java/MathFunctions/roundFloat
class MathFunctions:    @Description("round to given number of decimal places")
    @ScalarFunction("round")
    @SqlType(StandardTypes.REAL)
    public static long roundFloat(@SqlType(StandardTypes.REAL) long num)
    {
        return roundFloat(num, 0);
    }