VBA的 Round采用的是银行家算法（rounds to the nearest even number）
Round(1.5) = 2
Round(0.5) = 0
在Oracle中实现银行家算法
SQL> create or replace function bankers_round (val number, rnd_digit number := 0) return number is
2 v_rnd_digit number;
3 v_remainder number;
4 begin
5 v_rnd_digit := trunc(rnd_digit);
6
7 v_remainder := (val - trunc(val,v_rnd_digit)) * power(10,v_rnd_digit + 1);
8
9 if Abs(v_remainder) < 5
10 or (Abs(v_remainder) = 5 and mod(trunc(val * power(10,v_rnd_digit)),2) = 0) then
11 return trunc(val,v_rnd_digit);
12 else
13 return round(val,v_rnd_digit);
14 end if;
15 end;
16 /
SQL> select Bankers_Round(-123.45, 1) from dual;
BANKERS_ROUND(-123.45,1)
------------------------
-123.4
SQL> select Bankers_Round(-123.55, 1) from dual;
BANKERS_ROUND(-123.55,1)
------------------------
-123.6
SQL> select Bankers_Round(-123.65, 1) from dual;
BANKERS_ROUND(-123.65,1)
------------------------
-123.6
SQL> select Bankers_Round(-123.75, 1) from dual;
BANKERS_ROUND(-123.75,1)
------------------------
-123.8
在VBA中实现普通的四舍五入
Round(12.45+0.000000001,1)
http://blogs.msdn.com/b/ericlippert/archive/2003/09/26/bankers-rounding.aspx