presto-main/src/main/java/io/prestosql/operator/scalar/MathFunctions.java/MathFunctions/roundSmallint
class MathFunctions:    @Description("round to nearest integer")
    @ScalarFunction("round")
    @SqlType(StandardTypes.SMALLINT)
    public static long roundSmallint(@SqlType(StandardTypes.SMALLINT) long num)
    {
        return num;
    }